Huntington’s disease

Several different research studies have shown individuals with Huntington’s (or Huntington) disease (HD) have a lower body mass (body weight) than compared to people without HD. Theories as to why this occurs include increased metabolic expenditure due to chorea (uncontrollable movements), which uses more calories than usual, and decreased caloric intake due to difficulties with eating, chewing and swallowing.

Modified utensils and dishes for someone with HD can make eating easier. Also, working with a dietitian can be very beneficial to find healthy, high-calorie recipes for individuals with HD. The Huntington’s Disease Society of America (HDSA) has details about nutrition for people with HD on their website at http://hdsa.org/living-with-hd/nutrition/.

Studies show that the rate of depression is double that of the general population during the preclinical (before symptoms happen) and symptomatic period, for those with Huntington’s (or Huntington) disease (HD). It is not known whether this is associated with the changes occurring in the brain due to HD, or if it is associated with knowledge of having HD, and the lack of control over what is happening to the body.

Additionally, suicide is a real risk for families with HD. There are two peaks when suicide and suicidal ideation are most likely — just prior to receiving a diagnosis of HD, and again when symptoms of HD have progressed to a point when independence is lost.

It is important for families, caregivers, and people with HD to be aware of the risks and be educated on how to recognize risk factors for suicide and suicidal ideation. Establishing a relationship with a mental health provider early on is a helpful. Additionally, medications are commonly offered to help with depression and suicidal ideation, if a doctor knows they are occurring.

Reaching out to an advocacy or support group can help families and people with HD feel less alone. In the U.S., the Huntington’s Disease Society of America (or HDSA, a ThinkGenetic Advocacy Partner) offers many ways to connect and access resources about living with HD on their website at http://hdsa.org/living-with-hd/.

If you have Huntington’s (or Huntington) disease (HD), and genetic testing has confirmed your diagnosis, it is helpful to share your results with your family. Siblings and children are at risk to have also inherited HD and could consider genetic testing. Full siblings and children naturally share 50% of their DNA. This means that siblings and children of an individual with HD have a 50/50 random chance of having inherited HD as well.

A detailed family history can also provide information about which family members are at risk for developing HD. If symptoms or a diagnosis are not known for sure by looking at family history, offering a parent genetic testing can help to determine which side of the family the gene change for HD came from. This can allow extended family (aunts, uncles, and cousins) to know who is at risk so the focus can stay on them for the information and genetic testing discussions.

Genetic testing in at-risk adults that do not have symptoms ("predictive genetic testing") is available, but it is highly recommended that the genetic testing process include genetic counseling for guidance before and after genetic testing. Genetic testing is a highly personal decision. Medical evaluation of at-risk family members can also provide information about any symptoms or signs of HD.

In 2016, the Huntington’s Society of America (HDSA) in the U.S. has revised their genetic testing protocol, which provides information about the genetic testing process. To access this protocol, you can visit the HDSA website at http://hdsa.org/wp-content/uploads/2015/02/HDSA-Gen-Testing-Protocol-for-HD.pdf.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

One of the easiest ways to find other people with Huntington’s (or Huntington) disease (HD) is to connect with a support group for individuals and families affected by HD. In the U.S., the Huntington’s Disease Society of America website offers this information on their website at http://hdsa.org/about-hdsa/support-groups/. Online groups are also available.

May healthcare providers who specialize in HD have other patients/families who have agreed to be contacted by individuals who are reaching out after a new diagnosis or are in need of support.

Caring for a family member with Huntington’s (or Huntington) disease (HD) can bring different challenges, which may be emotional and physical. In the U.S., the Huntington’s Disease Society of America (HDSA) offers resources for caregivers, including webinars that are available online. To access these, please visit the HDSA website at http://hdsa.org/living-with-hd/caregivers-corner-webinars/.

If you have Huntington’s (or Huntington) disease (HD), you will likely need to see a few specialist doctors. You will need to see a neurologist. Other specialists may include psychiatrists, therapists, and mental health professionals who have experience in providing emotional support to people and families with HD. Lastly, occupational and physical therapists can help you maintain muscle strength and coordination for as long as possible while speech-language pathologists can assist with swallowing and communication issues. In addition, seeing a genetic counselor could help you to discuss genetic testing for your family members.

In the U.S., the Huntington’s Disease Society of America (HDSA) Centers of Excellence provide a multidisciplinary approach to the care and research of Huntington’s (or Huntington) disease (HD) across the country. To find the Center of Excellence nearest to you, go to http://hdsa.org/about-hdsa/centers-of-excellence/.

The usual abbreviation for Huntington’s (or Huntington) disease is HD.

The median timeframe of survival for someone with adult-onset Huntington’s (or Huntington) disease (HD) is 15-18 years after symptoms begin. The average age of death for a person with HD is 54-55 years of age. Some individuals live longer, especially if symptoms do not begin until a later age. Juvenile HD, which is rarer than adult-onset HD, has a rapid disease progression once symptoms begin. Death typically occurs in people with JHD within 10 years of the start of symptoms. Although there is no cure for HD, research and treatments continue to offer hope.

Juvenile Huntington’s (or Huntington) disease (JHD) is a less common form of HD where symptoms begins in childhood or adolescence. It starts at a younger age and has slightly different symptoms than adult-onset HD, but the cause is the same. It is also a progressive disorder that causes the breakdown of brain cells in certain areas of the brain. This results in uncontrolled movements, loss of intellectual abilities and emotional changes. JHD is defined by the onset of symptoms before age 20 years and accounts for 5-10% of all HD.

JHD is inherited in an autosomal dominant pattern and is caused by a mutation called a repeat of DNA (CAG trinucleotide repeat) in the HTT gene. Most often a child with JHD inherits the mutation repeat from their father, although on occasion a child can inherit it from their mother. JHD has a rapid disease progression once symptoms begin, with death typically occurring within 10 years of the start of symptoms. There currently is no cure. Treatment is supportive and focused on increasing quality of life.

Huntington’s (or Huntington) disease (HD) is a genetic condition that causes deterioration or death of cells, called neurons, in the brain. These are located in several areas of the brain including those that control movement, thinking, and behavior. The first symptoms of HD may be personality and behavioral changes, psychiatric problems, cognitive decline (affecting mostly processing, judgment, and logic). This may lead to a long delay in getting diagnosed.

HD also involves choreatic movements, which are rapid uncontrolled muscle movements (tics or jerks). These movements can occur all over the body and are not in someone’s control.

HD has a range of other symptoms as well, such as dystonia or unusual positioning of the body, significant weight loss, difficulty swallowing, and a loss of coordination. HD is progressive, which means that the disease gets worse with time, and eventually leads to death. Because this disease is progressive, it is referred to as a neurodegenerative disorder.

HD is a genetic disorder, which means it is inherited or passed down in families. It is inherited in an autosomal dominant manner. This means that individuals with HD have a 50% chance of passing on HD to each child they have. Neither the gender of the child nor the gene status of other children has any bearing on whether a specific child will inherit HD.

The onset of symptoms is often in adulthood, between the ages of 30 and 50. The symptoms become progressively worse over the next 10-25 years before the individual eventually passes away from complications of the disease like pneumonia or heart failure. More than 30,000 Americans are currently affected by this condition.

There can be significant health problems once symptoms of Huntington’s (or Huntington) disease (HD) begin. The main symptoms are involuntary movements (chorea), lack of coordination, impaired judgement, personality changes, and an unsteady gait. Individuals may experience depression, anxiety, and psychiatric conditions. Symptoms of HD become more severe as time passes, although the exact progression of symptoms is different from person to person. Initially, someone with HD remains independent, but as the disease progresses, they may need a full-time caregiver. Individuals with HD are at an increased risk for choking and infections. Due to the rapid worsening in cognitive abilities and coordination, people with HD are also at risk for falling and hurting themselves.

If you have symptoms of HD or someone in your family does, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

The HTT gene contains the instructions for a protein called huntingtin, which is important to brain cells (neurons). However, the function of the huntingtin protein is not fully understood. In those with Huntington’s (or Huntington) disease (HD), there is a repeated area of the HTT gene, called a trinucleotide repeat (CAG), that has grown too large and causes symptoms of HD. This CAG repeat expansion is the only known cause of HD. When there are longer repeats of the CAG region of the HTT gene, the huntingtin protein becomes larger and is cut up in smaller pieces that are toxic to the body. This is because the chopped up huntingtin protein builds up in the neurons of the brain — especially the areas that coordinate movement and control thinking. After time, the excess abnormal protein causes the death of the neurons.

Huntington’s (or Huntington) disease (HD) is caused by genetic changes in the huntingtin gene or HTT gene. The HTT gene is located on chromosome 4. The HTT gene contains the instructions for a protein called huntingtin, which is important to brain cells (neurons). However, the function of the huntingtin protein is not fully understood. In those with HD, there is a repeated area of the HTT gene code, called a trinucleotide CAG repeat, that has grown too large in the number of repeats and causes symptoms of HD. This CAG repeat expansion is the only known cause for Huntington’s disease.

The general population usually has 26 or less CAG repeats at this area of the gene. Having between 27 and 35 CAG repeats is considered in the "intermediate" category. This means that the individual is not at risk for developing symptoms of HD, but their children may be at risk to develop symptoms of the disease. This is because any number of repeats greater than 26 is unstable and the number of repeats can expand (get bigger) in the next generation. Having 36 -39 CAG repeats is considered "incompletely penetrant," which means that the person may or may not develop HD symptoms during their lifetime and can pass the gene expansion to their children. If a person has 40 or more of the CAG repeats, they will develop symptoms of HD as long as they live a typical lifespan, and can pass the gene expansion to their children.

If you have HD in your family, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

Considering whether or not to have genetic testing for Huntington’s (or Huntington) disease (HD) is a big and very personal decision. Not everyone in a family will want to have genetic testing. The process of predictive testing (genetic testing for someone that has no symptoms of HD but is at risk for them) often includes several appointments. These include meeting with a genetic counselor, meeting with a neurologist for a clinical exam, and talking with a psychologist to discuss readiness for testing.

In 2016, the Huntington’s Society of America (HDSA) in the U.S. has revised their genetic testing protocol, which provides information about the genetic testing process. To access this protocol, you can visit the HDSA website at http://hdsa.org/wp-content/uploads/2015/02/HDSA-Gen-Testing-Protocol-for-HD.pdf.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

The challenging thing about predictive testing for Huntington’s is that a positive test result does not clearly indicate when the symptoms will begin or how quickly they will progress. For this reason, some at risk individuals choose not to know because they feel it will take away from any years they have left prior to onset of symptoms. They feel that the anxiety of "waiting" for symptoms to occur will hinder their quality of life.

Others at risk feel that knowing their genetic status will allow them to better plan for the future — whether that is family planning, career selection, financial decisions, or other decisions.

If many family members are being tested at the same time, it may be difficult for families to cope with everyone’s results. For example, a sibling who tests positive for HD may feel both happy for a sibling who is negative but also wonder "Why me?" A sibling who tests negative for HD may feel relieved but also feel guilty for being "spared" when other family members have tested positive. These emotions are normal, but make the situation challenging.

There are many different factors to consider when thinking about having predictive genetic testing for HD. Regardless of what decision someone chooses, they are going to need support. It has been shown that depression, anxiety, and suicidal thoughts are more frequent when considering predictive testing and/or getting positive results.

Visit Huntington’s Disease Society of America to find support resources for Huntington’s disease in the U.S. For International support resources visit here. HDSA also funds Centers of Excellence across the U.S. that offer genetic counseling and testing, as well as access to HD knowledgeable neurologists, social workers, therapists and more. To find the Center of Excellence closest to you, go to www.hdsa.org/about-HDSA/Centers-of-Excellence/.

In the U.S., you can also find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

Mutations in the HTT gene cause Huntington’s (or Huntington) disease and juvenile HD. The HTT gene provides instructions for making a protein called huntingtin. Although the function of this protein is unknown, it appears to play an important role in nerve cells (neurons) in the brain. When the huntingtin protein is abnormally made, it can lead to the death of neurons in certain areas of the brain. This causes the signs and symptoms of juvenile HD. The HTT mutation that causes Huntington’s disease involves a DNA segment, known as a CAG trinucleotide repeat. This CAG repeat is made up of a series of three pieces of DNA (cytosine, adenine and guanine) that appear multiple times in a row. The CAG segment is repeated 10 to 26 times within the gene in people with HD or juvenile HD. In people with juvenile HD, the CAG segment is repeated more than 60 times.

A common sign of juvenile Huntington’s (or Huntington) disease (JHD) is a rapid decline in school performance. Symptoms can also include subtle changes in handwriting and slight problems with movement, such as slowness, rigidity, tremor, and rapid muscular twitching (myoclonus). Several of these symptoms are similar to those seen in Parkinson’s disease. These symptoms of JHD also differ from the chorea seen in people who develop HD as adults. Individuals with JHD may also have seizures and learning disabilities. The earlier the symptoms begin, the faster the disease seems to progress in someone. Death often follows within 10 years of the symptoms of JHD beginning in someone.

If you have signs of HD or someone in your family does, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

The main symptoms of Huntington’s (or Huntington) disease (HD) are involuntary muscle movements (chorea) of the hands, feet, face and trunk, lack of coordination, impaired judgement, personality changes, memory decline and an unsteady gait. However, it is important to note that the first symptoms of HD may be personality and behavioral changes, psychiatric problems, cognitive decline (affecting mostly processing, judgment, and logic). This may lead to a long delay in someone getting diagnosed. All these symptoms become more severe as time passes. Symptoms can also be split into 3 phases to describe the progression of the disease: early, middle and late. People progress through the symptoms and phases somewhat differently, and this cannot be predicted beforehand.

During the early phase, subtle personality changes and/or some involuntary movements can make performing daily tasks more difficult for someone. People in this stage may become more clumsy and be easily irritated or agitated. They may also not care about things they used to enjoy. Delusions or hallucinations can happen as well. Anxiety and depression are also common.

During the middle phase, movement and coordination issues become more obvious and speech can become very difficult for someone. People will begin to experience involuntary movements, chorea, and trouble with balance and walking. Reaction times will often slow and they will have trouble with controlling the speed and force of their movements. Often times, individuals in this stage may appear drunk to others who do not understand what is going on. Overall body mass also begins to decrease and people begin to become very slim — this is likely due to the involuntary movements burning more calories, as well as eating/swallowing difficulties.

During the late stage, people will generally be completely dependent upon a caregiver. Walking and speaking become nearly impossible. Muscles become very rigid and it’s difficult to start muscle movements. Choking is a serious risk as swallowing becomes more difficult. These symptoms usually progress over a period of 15-20 years. The average age of death is about 55 years of age.

If you have symptoms of HD or someone in your family does, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

The National Institute of Neurological Disorders and Stroke (NINDS) states that it is extremely important for someone with Huntington’s (or Huntington) disease (HD) to maintain physical fitness, as much as they can. Individuals who exercise and keep active tend to do better than those who do not. The Huntington’s Disease Society of America (HDSA) offers exercise tips for people with HD on their website, found at http://hdsa.org/hd-workout-tips/.

Despite these recommendations, research about exercise and HD has been conflicting. Some research has shown exercise to be beneficial, while other research has shown that it could be harmful. It is very important for a person with HD to consult their doctor so they can work together to develop an appropriate fitness plan.

Some of the earliest signs of Huntington’s (or Huntington) disease (HD) can include clumsiness, agitation, anxiety, depression, abnormal eye movements, and delusions. Individuals can also lose interest in activities they used to enjoy. Subtle motor (movement) changes and slower reaction times can also begin. The first signs of HD may be personality and behavioral changes, psychiatric problems, cognitive decline (affecting mostly processing, judgment, and logic). This may lead to a long delay in getting diagnosed, especially if there is no family history of HD.

If you have signs of HD or someone in your family does, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

Someone who had genetic testing showing the same CAG repeat size as in their family member with Huntington’s (or Huntington) disease (HD) should consider additional testing. While it can be frustrating and difficult to wait for more test results, additional testing can be helpful to clarify things. In this situation, the person’s doctor will offer additional testing to confirm the genetic test results. Working with a genetics professional, such as a genetic counselor, is highly recommended

To find a genetics clinic, discuss a referral with your doctor. Huntington’s Disease Society of America (HDSA) funds Centers of Excellence across the U.S. that provide genetic counseling and testing, as well as access to knowledgeable neurologists, social workers, therapists, and more. To locate a Center of Excellence close to you, go to: https://hdsa.org/about-hdsa/Centers-of-Excellence/

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

Currently, there is no cure for Huntington’s (or Huntington) disease (HD. There are treatments that focus on management of symptoms.

Some of the classes of medications used include neuroleptics and benzodiazepines to help with chorea (uncontrolled muscle movements). In the U.S., Tetrabenazine (Xenazine by Lundbeck) and deutetrabenazine (Austedo by Teva Pharmaceuticals) are the only FDA-approved drugs to specifically treat chorea in HD. Anti-Parkinson agents can be used to help with muscle rigidity. Additional drugs may be prescribed to prevent or manage seizures. Medications to improve depression and anxiety are also often considered. As with all medications, these can vary from person to person.

Supportive care extremely important for people with HD as they become more disabled. Skilled nursing-level care is often needed as the disease progresses.

People who currently do not have symptoms of HD and those at varying stages of the condition are encouraged to consider joining clinical trials or research studies to help improve treatment options and work towards a cure. Up-to-date information on clinical trials for HD can be found on the Huntington’s Disease Society of America website at http://hdsa.org/hd-research/enroll-in-a-clinical-trial/.

You can also find information at ClinicalTrials.gov at https://clinicaltrials.gov/ or Antidote at https://www.antidote.me/.

Newborn screening is available in many countries of the world. In the U.S., newborn screening is a state-run program that screens babies at birth for certain serious medical conditions that are common in newborn babies of that area, where treatment is available and can provide clear benefit. As of 2017, there is no newborn screening for Huntington’s (or Huntington) disease (HD).

Additionally, genetic testing is not typically done in young babies or people under age 18 for HD because symptoms do not usually show up in this age range. Genetic testing is also a personal decision, so waiting until someone is an adult to have genetic testing gives them a chance to make that choice.

There is only one type of DNA or genetic test for Huntington’s (or Huntington) disease (HD). In those with HD, there is a repeated area of the HTT (huntingtin) gene code, called a trinucleotide CAG repeat, is larger than usual. This causes changes in the HTT gene and leads to symptoms of HD. This CAG repeat is the only known cause for HD. Genetic testing determines the number of CAG repeats in the HTT gene that someone has. Genetic testing is used to help diagnose HD and for predictive testing of individuals at risk for HD (those who don’t have symptoms of HD, but have a family history of HD).

Due to the complexity or predictive genetic testing for HD, genetic counseling is recommended for guidance before and after testing. The predictive testing process is often done over a series of appointments that can include genetic counselors, neurologists and psychologists. This is to ensure that the at risk individual is ready to proceed with testing prior to having their blood drawn. Due to the nature of the disease, depression and thoughts about suicide are higher in families with HD. The genetic counseling and testing process helps to ensure that the at risk individual has help as they navigate their future.

In 2016, the Huntington’s Society of America (HDSA) in the U.S. has revised their genetic testing protocol, which provides information about the genetic testing process. To access this protocol, you can visit the HDSA website at http://hdsa.org/wp-content/uploads/2015/02/HDSA-Gen-Testing-Protocol-for-HD.pdf. You can also find frequently asked questions about predictive genetic testing on the HDSA website.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

There is currently clinical research going on for Huntington’s (or Huntington) disease (HD). Doctors specializing in HD should be aware of clinical trials available in the area.

Up-to-date information on clinical trials for HD can be found on the Huntington’s Disease Society of America website at http://hdsa.org/hd-research/enroll-in-a-clinical-trial/. The HDBuzz website also offers latest updates about research for HD, and can be found at https://en.hdbuzz.net/.

You can also find information at ClinicalTrials.gov at https://clinicaltrials.gov/ or Antidote at https://www.antidote.me/.

Prenatal testing is available if Huntington’s disease (HD) has been confirmed through genetic testing of the HTT gene in a parent beforehand. Prenatal testing is the process of testing a pregnancy to determine if it inherited a specific genetic condition. Prenatal genetic testing for genetic conditions that usually show up in adulthood has pros and cons, needs careful consideration, and genetic counseling is recommended beforehand.

Preimplantation genetic diagnosis (PGD) in which embryos can be genetically tested is also available. HD has to be confirmed through genetic testing of the HTT gene in a parent beforehand. During the PGD process, embryos are created through in vitro fertilization (IVF) by taking eggs from the mother and sperm from the father. The two are then combined in the laboratory. A few cells are removed from the embryo and are tested to determine if an embryo inherited the HTT gene that can cause HD. Then, the couple having PGD can choose to only have the embryos without HD transferred to the mother so she can carry the pregnancy. Additional steps are needed in PGD, it is not always covered by insurance, and this process has risks and benefits.

Genetic counselors are great resources to help families discuss the options for family planning. In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

If a parent has been diagnosed with Huntington’s (or Huntington) disease (HD), each child they have has a 50/50 random chance of having inherited HD. It does not matter whether the parent is a father or mother or if the child is a son or daughter; it is a 50% chance. The only way to know if a child has inherited the gene that can cause HD is through genetic testing. Genetic testing is typically done with a blood test after genetic counseling and careful consideration. If a person chooses not to get genetic testing, they will only know if they are going to develop HD if symptoms develop in him or her.

If you would like to learn more about genetic testing for HD and its pros/cons, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors). You can also learn a bit more about the genetic testing process in this document from the Huntington’s Disease Society of America: http://hdsa.org/wp-content/uploads/2015/02/HDSA-Gen-Testing-Protocol-for-HD.pdf

Doctors may prescribe a number of medications to help symptoms associated with juvenile Huntington’s (or Huntington) diseae (JHD). While medicines may help keep symptoms under control, there is currently no treatment to stop or reverse the progression of JHD. Anticonvulsant medications are usually prescribed to help prevent and control the seizures that occur in children with JHD. Tetrabenazine is often used to treat chorea (involuntary movements). Antipsychotic drugs such as haloperidol or other drugs such as clonazepam may also help to improve chorea, and may also be used to help control hallucinations, delusions, and violent outbursts. For depression, fluoxetine, sertraline, nortriptyline, or other drugs may be helpful. Tranquilizers can help control anxiety, and lithium may be prescribed to combat severe mood swings. As with all medications, these can vary from person to person.

People who currently do not have symptoms of JHD and those at varying stages of the condition are encouraged to consider joining clinical trials or research studies to help improve treatment options and work towards a cure. Up-to-date information on clinical trials for HD can be found on the Huntington’s Disease Society of America website at http://hdsa.org/hd-research/enroll-in-a-clinical-trial/.

You can also find information at ClinicalTrials.gov at https://clinicaltrials.gov/ or Antidote at https://www.antidote.me/.

The average age of onset of Huntington’s (or Huntington) disease (HD), meaning when symptoms begin in someone, is 35-44 years of age. In about 25% of HD, onset begins at age 50 or older. There have also been cases reported of disease onset after age 70. In the rare juvenile form of HD, symptoms can begin before age 20.

Juvenile Huntington’s (or Huntington) disease (JHD) is inherited in an autosomal dominant manner. This means that one copy of the change in the HHT gene is enough to cause symptoms of JHD. The gene change that causes symptoms is the repeat of 3 pieces of DNA, called CAG, over and over in the gene. Someone with JHD usually inherits the CAG repeat from a parent that has Huntington’s disease (the common, adult form). As the CAG repeat is passed from one generation to the next, the size can increase in size. A larger number of CAG repeats is usually associated with an earlier onset of signs and symptoms of JHD (called anticipation). Most often a child with JHD inherits the expanded CAG trinucleotide repeat from his or her father, although on occasion they inherit it from their mother.

To learn more about how JHD runs in families and/or genetic testing, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

Huntington’s (or Huntington) disease (HD) is genetic, and inherited in an autosomal dominant manner. This means the gene that causes it, called HTT, is one that both males and females have. Therefore, HD can affect males and females, and can be inherited from a mother or a father. When someone has HD, they have a 50/50 random chance to pass the gene change that causes it to their sons or daughters. This also means that there is a 50% chance that a parent with HD would not pass it to their children. Genetic testing can tell if the child has inherited the gene change; however, genetic testing usually takes place after the child has turned 18 and decides that they want to know this. Genetic testing cannot predict the exact timing of when symptoms will begin in someone, or what those symptoms will be.

HD is caused by a repeat of 3 pieces of DNA (specifically, CAG) that are repeated over and over in the HTT gene. This is also called a "trinucleotide repeat" or a "triplet expansion," and it can expand from generation to generation in a family.

Normally, a person has 26 or fewer CAG repeats in their HTT genes. However, if a person has 27-35 CAG repeats it is can cause symptoms of HD in them. This range of repeats is also considered "unstable" and has the potential to expand in the next generation. This expansion process can happen with each generation in a concept known as "anticipation." Once a person has 36 or more repeats, they are at risk of developing symptoms of HD and their gene can expand in their children. Also, for reasons not completely understood, large expansions (changes of more than 70 CAG repeats) occur almost exclusively through the father. They would have a 50/50 random chance of passing the expanded HTT gene to their sons or daughters.

If someone has more than 40 CAG repeats, they will develop symptoms of HD at some point in their lives. They also have a 50/50 random chance of passing the expanded HTT gene to their children.

If someone does not have the HTT gene that is/was in their parent, they cannot pass it on to their children.

To learn more about how HD runs in families and/or genetic testing, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

If you are interested in starting a support group for people with Huntington’s (or Huntington) disease (HD) in your area, you can reach out to the Huntington’s Disease Society of America (HDSA). The HDSA offers support and education for new support group leaders and you can email Anne Leserman, HDSA Community Services Manager, at [email protected]. More details about support groups that the HDSA offers can be found at http://hdsa.org/about-hdsa/support-groups/.

In the U.S., the Huntington’s Disease Society of America (HDSA) offers one of multiple ways to donate to help research in Huntington’s (or Huntington) disease (HD). You can make a financial donation, sign up for community walks, organize work place giving and more through this site. To visit their website, go to [link url="www.hdsa.org” target=”_blank”>www.hdsa.org and select "How To Help".

Huntington’s (or Huntington) disease (HD) is usually diagnosed by a medical evaluation, which may include a physical examination. Someone’s medical and family history are very helpful in making a diagnosis. Genetic testing can also be used to diagnose HD. If HD is suspected and/or there is a confirmed family history, a genetic counselor and/or medical geneticist can discuss genetic testing for HD, help order it, and go over the results. In many areas other healthcare professionals, such as neurologists, can also order HD genetic testing for individuals with HD and/or a family history of the disorder.

Genetic testing is typically done through a blood draw and the results usually take a few weeks (depending on the laboratory and where you are seen for the genetic counseling). While a blood test may seem simple and straightforward, the genetic testing process takes thought prior to deciding on it, and is very personal. This is especially if the genetic testing is done before someone has symptoms of HD. When that happens, it is considered "predictive genetic testing." Predictive genetic testing cannot currently tell us about the exact age the symptoms will appear, which ones will show up, or how they will progress.

Predictive genetic testing is often done over a series of appointments that can include genetic counselors, neurologists, and psychologists. This is done to ensure that the person considering testing is comfortable and ready to proceed with it before having their blood drawn. They may need time to think it over, discuss it with loved ones, and/or may decide not to proceed. Due to the nature of HD, depression and thoughts about suicide can be higher in families with HD. The genetic counseling and testing process helps to ensure someone has help as they navigate genetic testing and its future implications.

In 2016, the Huntington’s Society of America (HDSA) in the U.S. has revised their genetic testing protocol, which provides information about the genetic testing process. To access this protocol, you can visit the HDSA website at http://hdsa.org/wp-content/uploads/2015/02/HDSA-Gen-Testing-Protocol-for-HD.pdf.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

In the U.S., the Huntington’s Disease Society of America (HDSA) Centers of Excellence provide a multidisciplinary approach to the care and research of Huntington’s (or Huntington) disease (HD) across the country. To find the Center of Excellence nearest to you, go to http://hdsa.org/about-hdsa/centers-of-excellence/.

As soon as a diagnosis of juvenile Huntington’s (or Huntington) disease (JHD) is made in a child, it is important for the family to contact their school and begin to develop an individualized education plan (or IEP, as it is called in some areas). An IEP outlines how the school will address challenges caused by JHD that could interfere with the child s education.

Because JHD has many symptoms that can interfere, the IEP may include adjustments or variations in:

Genetics clinics and genetic counselors are helpful for individuals and families to learn about genetic conditions, treatment, inheritance, and genetic risks to other family members. To find a genetics clinic near you, contact your primary healthcare provider for a referral.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

In the U.S., the Huntington’s Disease Society of America (HDSA) Centers of Excellence provide a multidisciplinary approach to the care and research of Huntington’s (or Huntington) disease (HD) across the country. To find the Center of Excellence nearest to you, go to http://hdsa.org/about-hdsa/centers-of-excellence/.

The test for Huntington’s (or Huntington) disease is a blood test. DNA (that makes up a gene) is removed and analyzed. It is usually taken from the arm, like a normal blood draw. There are multiple labs available to do genetic testing in the U.S. and across the world. The lab choice is usually determined by someone’s doctor and/or genetic testing program.

In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

Huntington’s (or Huntington) disease (HD) has symptoms that vary over time, from person to person. This means that not every person affected by HD will have the same symptoms or the same timeline of disease progression. This progression cannot be precisely predicted beforehand. Some people with HD may begin to have symptoms at younger ages or have more severe symptoms more quickly after the disease begins. This is partly due to variability in the number of CAG DNA repeats in the HHT gene (which is what causes HD), and partly due to natural variability between people and families.

People with 36-39 CAG repeats in their HHT gene may or may not develop signs and symptoms of HD. This is considered an "intermediate" size of repeats and incompletely penetrant. Penetrance refers to how many people who inherit a genetic condition show the signs and symptoms of that condition. It is not clear why some individuals with 36-39 repeats develop HD and others do not.

Individuals with 40 or more CAG repeats are considered to be completely penetrant for the HHT gene. This means that they will — at some point in their lives — develop symptoms of HD. Again, the disease progression may not be the same for everyone and the exact symptoms cannot be predicted beforehand. Someone’s CAG repeat size can be determined through genetic testing.

If you have HD in your family or want to learn about genetic testing, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

Individuals with more than 35 CAG repeats in their HTT gene are at risk to develop symptoms of Huntington’s (or Huntington) disease (HD). However, those with 36-39 CAG repeats may or may not develop symptoms of HD. This is called "incomplete penetrance." If individuals with repeats in this range develop symptoms of HD, they usually have a later age of onset for their symptoms. Anyone with more than 40 CAG repeats will develop symptoms of HD if they live a typical lifespan; these are usually with symptoms beginning in the range of ages 35-44. If someone has over 60 CAG repeats, they are at risk of developing juvenile HD. In juvenile HD, symptoms typically begin prior to age 20.

If you have HD in your family, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

The number of CAG repeats (called CAG trinucleotide repeats) in the HTT gene determines whether a person develops Huntington’s (or Huntington) disease (HD). An increasing amount of CAG repeats can make the disease worse, and can mean an earlier presentation and more severe symptoms.The number of CAG repeats can also increase from generation to generation and this is called anticipation.

Individuals with 27-35 CAG repeats will not have symptoms of HD; however, if the repeats expand in the next generation, their children could develop symptoms of HD. Symptoms of HD develop when someone has CAG repeats of 40 or more, and they usually show up in adulthood. People with more than 60 CAG repeats will often develop symptoms of HD before age 20 — this is known as juvenile HD.

Avoiding smoking and alcohol use for people with HD can be helpful for symptom management. Additionally, avoiding L-dopa-containing compounds (often used for people with Parkinson’s disease) may increase chorea (uncontrollable movements that are a part of HD) in people with HD.

Symptoms of Huntington’s (or Huntington) disease (HD) may include personality and behavioral changes, psychiatric problems (like anxiety, hallucinations, and depression), or cognitive decline (affecting mostly processing, judgment, and logic) with no tics, twitches, or other movement issues. The symptoms not involving movement may be the first ones to show up in someone with HD. This may lead to a long delay in getting diagnosed.

Most people with Huntington’s (or Huntington) disease (HD) inherit it from a parent that has HD as well. However, rarely, someone gets HD due to a brand-new (de novo) change in the HTT gene (the gene that causes HD). In this case, others in the family would not usually have signs or symptoms of HD. The person with the de novo HTT gene change, however, would be able to pass it on to his/her children.

Neuroimaging refers to medical tests that can create pictures (images) of the brain. These include MRI, CT, and PET scans. Neuroimaging can be helpful so doctors can monitor progression of Huntington’s (or Huntington) disease (HD). Neuroimaging has also been used to look carefully at changes in the brain of someone with HD, even before symptoms begin in him/her.

Huntington’s (or Huntington) disease (HD) does not occur in one generation, skip the next generation, then show up in the next generation after that. However, HD may seem to skip a generation for one of the following reasons:

Huntington’s (or Huntington) disease (HD) affects both men and women of all ethnic backgrounds. However the frequency of the condition in different countries varies. In general, it affects about 3 to 7 per 100,000 people of western European background. A few isolated populations have an unusually high prevalence of HD. For example, the Lake Maracaibo region of Venezuela is believed to have the highest prevalence of HD in the world, with about 700 per 100,000 affected. HD occurs less frequently in Japan, China, and Finland as well as among people of African background.

The onset of symptoms is often in adulthood, between the ages of 30 and 50. The symptoms become progressively worse over the next 10-25 years before the individual eventually passes away from complications of the disease like pneumonia or heart failure.

There are two main forms of Huntington’s (or Huntington) disease (HD). These are adult HD and juvenile HD.

Adult HD is the most common of the two types. The average age of onset for symptoms in someone with adult HD is age 35-44. However, in 25% of individuals with adult HD, the onset of symptoms is after age 50. Sometimes symptoms of HD begin for the first time after the age of 70 — although,this is more rare.

Juvenile HD is less common and accounts for 5-10% of all HD. In juvenile HD, symptoms begin before age 20. Juvenile HD has slightly different signs and symptoms than adult HD. The progression of symptoms is usually quicker with juvenile HD, with death usually occurring 10 years after symptoms begin.

People with Huntington’s (or Huntington) disease (HD) should avoid compounds containing L-dopa, as they may increase chorea (involuntary movements that can happen in HD). L-dopa compounds may be used as treatments for people with Parkinson’s disease.

Alcohol and smoking are discouraged for people with HD.

The Huntington’s Disease Society of America (HDSA) website lists support groups and resources for Huntington’s (or Huntington) disease (HD) across the U.S., and these can be found at http://hdsa.org/about-hdsa/locate-resources/. HDSA is a ThinkGenetic Partner.

Other advocacy and support groups exist across the world as well. Asking your genetic counselor or other health care provider can help in identifying local resources and supports groups. In the U.S., you can find a genetic counselor near you by visiting the Find a Genetic Counselor website (by the National Society of Genetic Counselors) at http://www.nsgc.org/findageneticcounselor.

Other names for Huntington’s disease include:

When evaluating someone for Huntington’s (or Huntington) disease (HD), a doctor will usually consider several different things. If there is no family history of HD, they may consider early-onset Parkinson’s disease, dementia, or Alzheimer’s disease as possible diagnoses. Since HD is a rare condition, doctors may not consider it straight away, unless a family history of HD is also there. As HD progresses, though, the chorea or uncontrolled movements can strongly suggest it as the diagnosis. That timing can vary from person to person.

If there is a family history of HD, doctors will be more likely to include HD in their early list of diagnoses and be able to make a clinical diagnosis quicker, even if genetic testing has not been completed.

If you have HD in your family, you can speak to your doctor of contact a local genetic counselor. In the U.S., you can find a genetic counselor through the "Find a Genetic Counselor" website at http://www.nsgc.org/page/find-a-genetic-counselor (available through the National Society of Genetic Counselors).

There are several different health conditions that have similar signs or symptoms Huntington’s (or Huntington) disease (HD).The diagnosis may initially be difficult when the family history is not known.
Some of the conditions that can look like HD include (not a comprehensive list):