Cystinosis is a genetic condition in which an amino acid called cystine builds up in the cells of the body as a result of changes or mutations in a gene called CTNS. Due to these CTNS gene mutations, people with cystinosis lack enough of an enzyme called cystinosin. Cystinosin helps move, or transport, cystine out of the cells. If people lack this enzyme or if the enzyme doesn’t work properly, then cystine will build up in the cells. As cystine builds up it forms crystals which interrupt cell function leading to early cell death and organ damage.
Although any muscle can be damaged by high levels of cystine,the kidneys and eyes are most often affected in people with cystinosis. The liver, muscles, pancreas, and brain are also commonly affected. Cystinosis can be very different in how it affects people. Three different forms have been identified: nephropathic cystinosis, about 95% of people who have cystinosis have this form; juvenile nephropathic cystinosis, about 3% of people with cystinosis have this form; and non-nephropathic cystinosis. Even within each type of cystinosis people will have different health problems and speed of disease progression.
There are FDA approved treatments for cystinosis; however, it is important to diagnose and treat cystinosis early to slow down the disease and have the best health outcomes. Doctors treat the disorder with drugs that lower the levels of cystine in the body and specifically in the eyes. Even with treatment, most people who have nephropathic or intermediate cystinosis will eventually need a kidney transplant.
Cystinosis may also be known as:
CTNS
Defect of cystinosin
Defect of lysosomal cystine transport protein
The different forms of cystinosis are:
Nephropathic cystinosis, also known as infantile nephropathic cystinosis. This form becomes apparent within the first year of life.
Juvenile nephropathic cystinosis, also known as intermediate cystinosis or adolescent nephropathic cystinosis. This form becomes apparent between 6-8 years of age.
Non-nephropathic cystinosis, also known as ocular cystinosis. Primarily affects the eyes, causing bright lights to hurt the eyes (photophobia). This form becomes apparent during adulthood.
Cystinosis affects around 1 out of every 100,000 to 200,000 people in the general population. The disorder has been reported in individuals of every ethnic group and throughout the world. Cystinosis causes about 5% of all instances of childhood kidney failure.
Frequently Asked Questions About Cystinosis
Will my child with cystinosis need dialysis?
Dialysis is a procedure in which a machine is used to perform some of the functions of the kidney – filtering waste products from the bloodstream, helping to control blood pressure, and helping to maintain proper levels of essential chemicals. People with nephropathic cystinosis and intermediate cystinosis will eventually require a kidney transplant. Sometimes they may need to be on dialysis while waiting for a new kidney.
Will cystine crystals form in a transplanted kidney?
If cystinosis patients receive a kidney transplant and reach adulthood, their new kidney will not be affected by the disease. Cystine cystrals may be seen in the new kidney because host cells may enter the new kidney. There is no clinical significance of this finding.
Why does cystine accumulate in cystinosis?
The CTNS gene produces a protein known as cystinosin, which is required to move, or transport, cystine out of lysosomes (the "recycling centers" of the body’s cells). Since it can’t be moved out of the lysosome, the cystine builds up in the cells. As cystine builds up it forms crystals which interrupt cell function leading to early cell death and organ damage.
Why are there compliance issues with cystinosis?
The treatment of cystinosis includes taking a drug, either Cystagon or Procysbi, that must be taken daily, either 4 or 2 times a day. Some people may choose to stop taking the drug because of side effects. This is called poor compliance. Cystagon or Procysbi both have side effects. They taste and smell bad and when people use them they may have bad breath or develop a body odor. Children, particularly older children, may stop taking a drug because they are embarrassed or their classmates may make unkind comments. Children or teenagers who struggle with compliance should talk to their parents, physicians and a psychologist to work through these issues.
Sometimes people stop taking a drug because it’s working well and they feel better. They may start to think that they do not need the drug anymore or as often as their doctors recommend. However, cystine will keep building up in the cells throughout life, even if you start to feel better. Stopping one of these drugs will lead to even more cystine build up. These drugs must be taken every day. Even if someone feels better and their symptoms improve, they need to continue to follow their treatment plan as developed by their physician and medical team in order to continue feeling better.
Cystinosis support groups have information about how to handle compliance problems. The Cystinosis Foundation offers a booklet called Nephropathic Cystinosis: A Guide for Parents, Patients and Healthcare Professionals. The Cystinosis Research Networks offers booklet called, Cystinosis Parent Handbook.
Where can I talk to other people with cystinosis?
The cystinosis support groups can put you in contact with other people or families that have cystinosis. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
There are also online communities for rare disorders such as [link url="www.bensfriends.org/” target=”_blank”>Ben’s Friends, RareConnect, RareShare, or Inspire, which allow individuals and parents to share experiences and advice about dealing with rare disorders.
What tests are used to diagnosis cystinosis?
Several different tests may be used to diagnose cystinosis. High cystine levels in certain white blood cells called suggest a diagnosis. Molecular genetic testing can be used to study the CTNS gene to identify variations or changes in the gene that lead to cystinosis. This can include targeted mutation analysis, where specific, known changes in a gene are looked for; sequence analysis, where a part or sequence of DNA within a gene is examined; or deletion/duplication analysis, where missing or extra regions of DNA are looked for within a specific gene. Testing of white blood cells or molecular genetic testing must be down at specialized laboratories.
Additional tests may be used to see what other symptoms are present and how severe they are. For example, physicians will run tests to evaluate the health and function of the kidneys such as a renal ultrasound.
The easiest way to begin testing for cystinosis is to discuss it with the pediatrician or primary doctor. A list of doctors who specialize in cystinosis can be found on the Cystinosis Research Network Expert doctor list. Testing information in your area can also be obtained through a genetic counselor, to find a genetic counselor visit the National Society of Genetic Counselors Find a Genetic Counselor website.
What is cystinosis?
Cystinosis is a genetic condition in which an amino acid called cystine builds up in the cells of the body as a result of changes or mutations in a gene called CTNS. Due to these CTNS gene mutations, people with cystinosis lack enough of an enzyme called cystinosin. Cystinosin helps move, or transport, cystine out of the cells. If people lack this enzyme or if the enzyme doesn’t work properly, then cystine will build up in the cells. As cystine builds up it forms crystals which interrupt cell function leading to early cell death and organ damage.
Although any muscle can be damaged by high levels of cystine,the kidneys and eyes are most often affected in people with cystinosis. The liver, muscles, pancreas, and brain are also commonly affected. Cystinosis can be very different in how it affects people. Three different forms have been identified: nephropathic cystinosis, about 95% of people who have cystinosis have this form; juvenile nephropathic cystinosis, about 3% of people with cystinosis have this form; and non-nephropathic cystinosis. Even within each type of cystinosis people will have different health problems and speed of disease progression.
There are FDA approved treatments for cystinosis; however, it is important to diagnose and treat cystinosis early to slow down the disease and have the best health outcomes. Doctors treat the disorder with drugs that lower the levels of cystine in the body and specifically in the eyes. Even with treatment, most people who have nephropathic or intermediate cystinosis will eventually need a kidney transplant.
What gene change causes cystinosis?
All three forms of cystinosis are caused by changes or mutations in the CTNS gene. Genes produce specific instructions in the form of proteins that the body needs to grow and work properly. When there is an change in a gene, the protein that the gene produces may be absent, deficient, or faulty and ineffective. In cystinosis, the CTNS does not make enough of the specific enzyme protein called cystinosin. Cystinosin helps move, or transport, cystine out of the cells. If people lack this enzyme or if the enzyme doesn’t work properly, then cystine will build up in the cells. As cystine builds up it forms crystals which interrupt cell function leading to early cell death and organ damage.
In rare instances, the CTNS gene and other nearby genes are missing or deleted. This can also cause cystinosis, but these individuals usually have a more complex disorder because of the loss of additional genetic material.
What drugs are in clinical trials for cystinosis?
There are a couple new drugs currently (June 2016) in various stages of clinical trial review for cystinosis. The drug, N acetyl cysteine, is being studied to see whether it interferes with the progression of kidney disease in nephropathic cystinosis. In Europe, Cystadrops® (cysteamine hydrochloride) made by Orphan Europe is being studied. This is a new gel formation type of eye drop that is being studied to treat the build up of cystine crystals in the corneas of the eyes.
To learn about ongoing clinical research into cystinosis ask a physician who specializes in the disorder. Genetic counselors and medical geneticists are also excellence sources of information about ongoing clinical trials and can offer advice about the pros and cons about participating in such a trial.
Ongoing studies for cystinosis can also be found on clinicaltrials.gov, a service of the U.S. National Institutes of Health. In Europe, the EU Clinical Trial Register performs a similar service.
Support groups also have information about ongoing clinical trials as well as information and advice about participating in clinical trials. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
What does it mean to inherit a variant in the gene for cystinosis?
There are more than 100 genetic mutations or changes associated with cystinosis. A genetic mutation refers to a specific gene change in the CTNS gene that causes cystinosis. Some gene changes such as the 57-kb deletion are common. Other gene changes may be unique to a family. CTNS is the only gene known to cause cystinosis. Sometimes certain symptoms are more likely to occur with a specific gene change.
What doctors do I need to see to manage and treat cystinosis?
It is recommended that individuals with cystinosis be seen by a team of doctors with experience in treating the disorder. This will require physicians from multiple medical disciplines including a specialist for kidney disorders in children (pediatric nephrologist), an eye doctor (ophthalmologist), a metabolic disease specialist, a specialist in neurological disorders (neurologist), a specialist in digestive disorders (gastroenterologist), genetic counselors, psychologists, and nutritionists.
What do I need to know about kidney transplants for cystinosis?
Many people with cystinosis will eventually require a kidney transplant for end stage renal disease. During this procedure, the donor kidney is surgically placed into the patient whose own kidneys have stopped working effectively. The new kidney will take over performing vital functions such as removing waste products and regulating fluid levels. Only one kidney is needed to replace the two that have stopped working. A person’s original kidneys are usually not removed. After a transplant, a person will be required to take drugs that suppress the immune system to prevent rejection of the kidney. Immunosuppressive drugs must be taken daily for life. Kidneys from living donors or from people who are deceased (cadaveric kidneys) have both been used to treat kidney failure in cystinosis and have performed well, although live donors are preferred.
Children with cystinosis and kidney failure often see dramatic improvement after a transplant. Growth may increase significantly and energy levels often improve. However, a kidney transplant does not prevent cystine from building up in other organs and individuals will have to keep taking Cystagon or Procysbi to prevent damage to other organs even after a successful kidney transplant.
For more detailed information on kidney transplants contact one of the cystinosis support groups (the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK) or the National Kidney Foundation can provide detailed information.
What are the subtypes of cystinosis?
The different forms of cystinosis are:
What are the main symptoms of cystinosis?
Three different types of cystinosis have been identified: nephropathic cystinosis, juvenile nephropathic cystinosis, and non-nephropathic cystinosis. Each type of cystinosis results in health problems caused by the build up of cystine, but the age at which problems start, the types of health problems, and speed of disease progression is different. In all forms, the kidneys and eyes are the most commonly affected body parts.
Nephropathic cystinosis is the most severe form of the disease. It usually becomes apparent between 6 months and 1 year of life. Most children look fine at birth, but are already starting to have silent health issues. The usual first signs of nephropathic cystinosis are poor weight gain, delayed growth, and a distinctive kidney condition known as renal Fanconi syndrome. Renal Fanconi syndrome occurs when the small tubes (tubules) of the kidney do not function well and fail to reabsorb nutrients including water, glucose, amino acids, carnitine, and various minerals and electrolytes. Symptoms include excessive thirst, urinating a lot, passing large amounts of urine, dehydration, and vomiting. These problems contribute to poor weight gain and delayed growth.
Dehydration can be severe in babies with nephropathic cystinosis. Infants are at risk for metabolic acidosis, in which the chemical balance of the body becomes too acidic because the kidneys fail to remove enough acid from the body. A baby may need to go to the hospital during a severe episode because of a profound loss of blood volume known as hypovolemia; the risk is greater during a gastrointestinal illness.
In nephropathic cystinosis, the damaged kidneys may fail to absorb phosphorous which can lead to rickets, a childhood bone disease that occurs during growth and leads to softening and weakness of affected bones and bowing of the legs. Rickets is painful and can delay walking in a child or cause a child to walk gingerly.
In nephropathic cystinosis, if the kidneys fail to reabsorb enough calcium, seizures or cramping muscles spasms known as tetany may develop. When left untreated, kidney function in children with nephropathic cystinosis will worsen until the kidneys fail to work, usually by the age of 10. This is known as end stage renal failure.
In nephropathic cystinosis, medications that lower cystine levels in the body can slow kidney damage and delay the need for a kidney transplant for many years. Any kidney damage that occurs before treatment is started cannot be fixed.
Children with nephropathic cystinosis can also develop cystine crystals in the eyes at any point during childhood. These crystals cause bright lights to hurt the eyes, a condition known as photophobia. Sometimes painful erosions on the corneas can develop.
Between 5-10 years of age, many untreated children with nephropathic cystinosis will develop hypothyroidism. Hypothroidism occurs when thyroid gland does not produce hormones like it should. Symptoms include sensitivity to cold, fatigue, dry skin, constipation, muscle weakness, hoarseness, and depression.
Intelligence is usually average in nephropathic cystinosis, but learning disabilities can occur. Some children will display difficulties processing visual information (e.g. telling shapes apart), short-term visual memory, or recognizing spacial relationships like the distance between two objects.
Some children with nephropathic cystinosis may not produce tears, saliva, or sweat as well as children without cystinosis. These issues can lead to dry eyes, dry mouth, or heat prostration, a condition in which a child passes out or collapses because of the heat. Some children may not get their permanent teeth until older than normal. Certain facial features may be mildly altered. Puberty can be delayed by a year or two and some boys may not produce enough testosterone (hypogonadism).
In nephropathic cystinosis, increased pressure within the brain, known as intracranial hypertension, can cause headaches or swelling of the optic disk. Enlargement of the liver or the spleen can occur, also called hepatosplenomegaly, usually by 15 years of age. Young adults can develop muscle weakness. Insulin-dependent diabetes mellitus can develop in the teen-age years or during the 20s.
There is no reliable way to predict in an individual when and if additional symptoms will develop in nephropathic cystinosis. One important factor in determining the progression of the disorder is the age and extent of the disease when treated is first begun.
Juvenile nephropathic cystinosis, also known as intermediate cystinosis or adolescent nephropathic cystinosis. This form becomes apparent between 6-8 years of age and results in symptoms very similar to the earlier onset form. Health problems can be very different from child to child, but the disease always gets worse without treatment.
Non-nephropathic cystinosis, also known as ocular cystinosis results in a milder form of cystinosis. Ocular cystinosis primarily affects the eyes, causing bright lights to hurt the eyes (photophobia). This type of cytinosis is found usually during adolescent or adulthood and usually doesn’t affect the kidneys.
What are the first steps after an initial diagnosis of cystinosis?
After getting a diagnosis of cystinosis, people will go through a series of tests to see how far along the disease is. These tests will tell a physician what parts of the body are affected and to what extent. For example, tests will be used to tell how well the kidneys are working. Most people will immediately be put on drugs that lower the levels of cystine in the body. Early treatment is important because these drugs can slow the development or progression of symptoms. Other initial steps will depend on how the disorder is affecting a person. For example, some children may need to take nutritional supplements because of feeding problems or kidney disease. Families should see a cystinosis specialist and/or a geneticist and a genetic counselor to help understand the genetic aspects of this disorder. A list of doctors who specialize in cystinosis can be found on the Cystinosis Research Network Expert doctor list. To find a genetic counselor near you, visit the National Society of Genetic Counselors Find a Genetic Counselor website.
What are the differences between medications used to treat cystinosis?
Decisions concerning how to treat cystinosis should be made after talking to a physician and medical team. The two main full body treatments for cystinosis, Cystagon and Procysbi, work by lowering cystine levels within the cells. These drugs are taken by the mouth (orally). Cystagon is taken every 6 hours (or 4 times a day). Procysbi is taken every 12 hours. Side effects of both drugs include nausea, vomiting, and gastrointestinal discomfort. They can also cause too much stomach acid to be produced. Some patients also find that Cystagon has a strong taste and smell and can cause a person to have bad breath and to smell badly. These issues have led to patients not taken the recommended dose (compliance problems).
Should other family members be tested for cystinosis?
In a family with cystinosis, other testing can be done to see whether at-risk family members are carriers for the disorder. However, the specific gene changes in that family must be known. If known, all siblings of an affected child can be tested to see whether they have the disorder or whether they are carriers. A newborn child in such a family must be tested either through a test that looks for a gene change (if known for that family) or a test that can measure certain chemical levels in the body. A genetic counselor or physician with experience in cystinosis can provide advice about how a diagnosis of cystinosis can impact other family members. To find a genetic counselor near you, visit the National Society of Genetic Counselors Find a Genetic Counselor website. A list of doctors who specialize in cystinosis can be found on the Cystinosis Research Network Expert doctor list. .
Is there newborn screening for cystinosis?
Cystinosis is not one of the disorders that is detected through newborn screening in 2016. Researchers are trying to come up with the best way to test all babies for cystinosis at birth. A small study testing some babies for cystinosis at birth may begin in one state soon. If a baby appears to have health problems that could be caused by cystinosis, the easiest way to begin testing for cystinosis is to discuss it with the pediatrician or primary doctor. A list of doctors who specialize in cystinosis can be found on the Cystinosis Research Network Expert doctor list. Testing information in your area can also be obtained through a genetic counselor, to find a genetic counselor visit the National Society of Genetic Counselors Find a Genetic Counselor website.
Is there clinical research happening on cystinosis?
As of June 2016, there are 23 studies for cystinosis listed on clinicaltrials.gov, a government website that provides regularly updated information about federally and privately supported research and clinical trials. This is not an exhaustive list of current research. Current studies are looking at new treatments, more effective ways to use existing treatments, and the consequences of specific changes to the CTNS gene. Research is also ongoing to find a way to identify cystinosis through newborn screening.
To learn about ongoing clinical research into cystinosis ask a physician who specializes in the disorder. Genetic counselors and medical geneticists are also excellence sources of information about ongoing clinical trials and can offer advice about the pros and cons about participating in such a trial.
Ongoing studies for cystinosis can also be found on clinicaltrials.gov, a service of the U.S. National Institutes of Health. In Europe, the EU Clinical Trial Register performs a similar service.
Support groups also have information about ongoing clinical trials as well as information and advice about participating in clinical trials. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
Is there a treatment for cystinosis?
The treatment of cystinosis focuses on the specific symptoms that are apparent in each individual. Given the number of medical problems that can be seen in cystinosis, treatment often requires a team of doctors with different areas such as: pediatricians, kidney specialists (nephrologists), eye specialists (ophthalmologists), digestive disorder specialists (gastroenterologists), medical geneticists, genetic counselors, psychologists and other healthcare professionals.
Combined with symptom specific treatments, three medications have been approved for the treatment of cystinosis by the U.S. Food and Drug Administration (FDA): Cystagon® (cysteamine bitartrate), Procysbi ®, an extended release form of cysteamine, and Cystaran®, cysteamine ophthalmic solution. Cystaran®, cysteamine ophthalmic solution, made by Sigma-Tau Pharmaceuticals is also approved by the FDA to treat the eyes specifically and is given as eye drops. It is the only option for treating the eye issues seen in cystinosis. In 1994, Cystagon® (cysteamine bitartrate), marketed by Mylan Pharmaceuticals, was the first treatment approved for cystinosis. In 2013 Procysbi ®, an extended release form of cysteamine made by Raptor Pharmaceuticals, was approved. Both Cystagon® and Procysbi ® lower cystine levels within cells. When started early enough these drugs can prevent hypothyroidism, enhance growth and weight gain, slow the progression of kidney disease, and delay or prevent other symptoms. Although these medications are not a cure, they along with improvements in kidney transplants, have greatly improved the quality and length of life in people with cystinosis. Children with the disorder can delay the need for a kidney transplant into their 20s and life expectancy is now well into adulthood even past age 50. These two drugs cannot treat cystine build up in the corneas of the eyes.
I am a carrier of cystinosis, will I develop symptoms?
Carriers of the CTNS gene associated with cystinosis do not develop symptoms of the disorder.
How likely is cystinosis to be passed on in a family?
In cystinosis, both parents must pass along a nonworking copy of the CTNS gene in order for their child to have cystinosis. For each individual pregnancy, there is a 25% chance that both parents will pass along a nonworking copy of the gene and the child will have the disorder. There is a 50% chance that one parent will pass on the gene change and the other won’t, meaning the child will be a carrier for the disorder. There is a 25% chance that both parents will pass along a working copy of the gene and the child will not have the disorder and will not be a carrier.
How is cystinosis inherited?
Cystinosis is inherited in an autosomal recessive manner through a family. Everyone has two copies of the CTNS gene; one received from their father and one from their mother. Autosomal recessive inheritance means that in order to have the disease, a person must receive a nonworking copy of the CTNS gene from both parents. The parents have one working copy of the gene and one nonworking copy; they are carriers for cystinosis. Carriers, also known as heterozygotes, do not develop symptoms of the disorder. In order to cause cystinosis, both parents must pass along a nonworking copy of the CTNS gene in order for their child to have cystinosis. For each individual pregnancy, there is a 25% chance that both parents will pass along a nonworking copy of the CTNS gene and the child will have the disorder. There is a 50% chance that one parent will pass on the gene change and the other won’t, meaning the child will be a carrier for the disorder. There is a 25% chance that both parents will pass along a working copy of the gene and the child will not have the disorder and will not be a carrier.
How do the different types of cystinosis differ?
Nephropathic cystinosis develops within the first year of life and when untreated leads to severe symptoms related to kidney failure as well as eye, liver, muscle, and pancreas issues. The symptoms of intermediate cystinosis are the same or similar to those of nephropathic cystinosis, but they do not develop until 6-8 years of age. Non-nephropathic cystinosis usually occurs in teens and adults. If untreated, adults develop cystine crystals in the eyes and some degree of light sensitivity. They do not develop kidney disease or other symptoms of the disorder.
How do I give money to support research on cystinosis?
Support groups have information about supporting research into cystinosis and most accept donations toward research. Some groups focus specifically on supporting research. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
How do I get tested for cystinosis?
Nephropathic cystinosis should be suspected in a child who does not grow and gain weight very well and who has symptoms of renal Fanconi syndrome. These symptoms include urinating a lot, passing large amounts of urine, and losing large amounts of minerals and electrolytes through the urine. A urine sample can be tested to detect minerals, electrolytes, amino acids, and carnitine. The urine may also contain a lot of water. An early diagnosis of nephropathic cystinosis is important because drugs that lower the cystine levels in the body can slow or prevent specific symptoms.
There are three main tests that can help to confirm a diagnosis of nephropathic cystinosis:
How do I find clinical research on cystinosis?
To learn about ongoing clinical research into cystinosis ask a physician who specializes in the disorder. Genetic counselors and medical geneticists are also excellence sources of information about ongoing clinical trials and can offer advice about the pros and cons about participating in such a trial.
Ongoing studies for cystinosis can also be found on clinicaltrials.gov, a service of the U.S. National Institutes of Health. In Europe, the EU Clinical Trial Register performs a similar service.
Support groups also have information about ongoing clinical trials as well as information and advice about participating in clinical trials. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
How do I find a treatment center with experience in cystinosis?
One of the best ways to find a treatment center or physician with experience in treating cystinosis is to contact a national cystinosis support group. Support groups for cystinosis include the Cystinosis Research Foundation, Cystinosis Research Network, the Cystinosis Foundation, and Cystinosis Foundation UK.
A list of doctors who specialize in cystinosis can be found on the [Cystinosis Research Network Expert doctor list.
How do children with cystinosis go from pediatric care to adult care?
Many people with cystinosis find it challenging when it’s time to move (transition) from pediatric to adult care services. One big change is leaving a doctor with whom you have a long-standing relationship, a doctor who is familiar with both your condition and yourself. It can feel like ‘starting over’ as you’ll begin to work with new doctors and a new medical team. Another challenge in moving to adult care is that young adults must take greater responsibility for their health. They must manage their disorder and manage their medications. They must bear greater responsibility for decisions concerning their health. Some hospitals have programs to help children with chronic disease transition to adult care services. Cystinosis support groups may also provide information or support on how to move from pediatric care to adult care services and what to expect.
The Cystinosis Research Network offers booklet called A Transition Guide for Teens and Young Adults with Cystinosis and their Families that offers advice on this topic. Talk to your child’s doctor about how and when to take steps to begin transition to adult care.
How do children with cystinosis do in school?
Children with cystinosis can do well in school. Intelligence and school performance is usually average. Some children may have specific learning disabilities such as problems with visual processing. Some children may need special accommodations such as the need to wear sunglasses in class, have water or snacks in class, or take medications while at school. Children with cystinosis are eligible for an individual education plan (IEP) or a 504 plan. An IEP is a document that helps to guide the education of a child with a disability or special needs. The plan is individualized for each student. A 504 plan ensures that students with disabilities can fully participate in school and have access to the same educational opportunities as all children. Parents are encouraged to provide a school with a packet of information on cystinosis and to work with school officials including teachers, nurses, psychologists, the principal, and other professionals.
The U.S. Department of Education has information on individual education plans and on 504 plans.
Cystinosis support groups have information and advice on how to handle schooling for children with cystinosis. The Cystinosis Research Network offers a booklet called the Cystinosis Patient Handbook, which includes information about schooling.
How common is cystinosis?
Cystinosis affects around 1 out of every 100,000 to 200,000 people in the general population. The disorder has been reported in individuals of every ethnic group and throughout the world. Cystinosis causes about 5% of all instances of childhood kidney failure.
How are the kidneys treated in cystinosis?
Nephropathic and intermediate cystinosis cause progressive kidney damage. Once kidney damage occurs, it cannot be reversed. Although the drugs Cystagon and Procysbi can slow the progression of kidney disease, individuals with nephropathic and intermediate cystinosis will still need a kidney transplant at some point in their lives. However, some individuals with nephropathic cystinosis delay the need for a transplant into their 20s or longer. As kidney function worsens, supportive therapy will become necessary. This can include taking in a lot of water and fluids and taking supplements to replace the mineral and electrolytes that are lost through poor kidney function. Drugs known as ACE inhibitors can be given to help slow down the loss of kidney function. Some children are given indomethacin, a drug that can reduce the loss of water and electrolytes in the kidney. However, this requires that children be closely monitored.
How are the eyes treated in cystinosis?
Cystaran®, made by Sigma-Tau Pharmaceuticals, was approved by the FDA in 2012 to treat cystine build up in the eyes. This drug is given by eye drops, around 8-12 times a day. If patients follow the recommended dose and schedule, eye problems usually clear up within a few weeks, but can take longer. Avoidance of bright lights and the use of sunglasses and lubricants for the eyes can help people who are sensitive to bright light.
Does my child with cystinosis need to be on a special diet?
Young children with cystinosis can fail to grow and gain weight in early childhood. They might need to follow a high calorie diet early in life to ensure that they receive proper nutrition. Current dietary recommendations for cystinosis include replacing the loss of vital nutrients including amino acids, glucose, phosphate, calcium, magnesium, sodium, potassium, carnitine, bicarbonate, and water by taking supplements or through the use of a gastronomy tube. Some children will crave salty foods. Because of kidney disease, unrestricted access to water and salt is recommended. There are no foods that children or adults with cystinosis need to avoid, but all people should follow a balanced, healthy diet. Depending on what a person’s individual symptoms are, recommendations about diet may vary from person to person with cystinosis. Ask your child’s doctor for personalized recommendations. To find a dietitian who specializes in treating people with conditions like cystinosis you can search the GMDI Find a Metabolic Dietitian website.
Does anything beside a gene change cause cystinosis?
Cystinosis is caused by changes to the CTNS gene. More than 100 different genetic changes in the CTNS gene have been identified. A specific change may be more likely to cause certain symptoms. Researchers have also learned that many genetic disorders are influenced by environmental and changes in other genes (called modifier genes). Physicians are trying to figure out how different changes in the CTNS gene can lead to different cystinosis types and to determine whether anything else can influence how cystinosis develops in a person.
Do women with cystinosis need to stop taking their medication when they want to get pregnant?
Toxic and developmental (teratogenic) effects of cysteamine have been observed in animals. No studies have been done to assess the risk in women who are pregnant. Consequently, cystine-lowering drugs are not used (contraindicated) during pregnancy, particularly in the first trimester. Family planning is recommended in women of childbearing age. In addition, cysteamine administration should also be avoided during breastfeeding. Discuss how treatment may need to be adjusted during pregnancy with your physician.
Do I need to start drug treatment immediately for cystinosis?
Treatment with cysteamine should be considered in all patients upon diagnosis regardless of age or transplantation status. Cysteamine eye drops are usually begun when someone begins having problems with or is sensitive to bright lights (photophobia).
Can women with cystinosis have difficulty becoming pregnant or having successful pregnancies?
Women with cystinosis have had successful pregnancies. The newborns have been healthy as well. Cystinosis is an autosomal recessive disease and the risk of someone with cystinosis having a child with the disorder is extremely low. Women with cystinosis are at a higher risk for premature delivery and proper precautions and monitoring is necessary. If women have kidney disease, special attention must be paid to their fluid or electrolyte status. Women with cystinosis who are pregnant or considering pregnancy should make their obstetrician aware of their condition to learn more about proper treatment and monitoring during pregnancy.
Can family members donate a kidney to someone with cystinosis?
Relatives of people with cystinosis could be acceptable donors for a kidney transplant. As there are many factors that determine whether or not someone is an acceptable kidney donor, speak to your specialist to learn more about what requirements would need to be met.
Can cystinosis be detected before birth?
Although it is not looked for routinely on every pregnancy, parents may choose to have their child tested for cystinosis during pregnancy. This is known as prenatal diagnosis and can be done through a few different tests. In the first, a test called chorionic villus sampling, a sample of tissue can be take from the early placenta to test for the gene change that causes cystinosis in the family. Another test is called amniocentesis, which involves taking a sample of the amniotic fluid that surrounds a developing fetus. Cells known as amniocytes are taken from the fluid and studied. If the gene changes that cause cystinosis is known in a family, then genetic testing that can detect these changes can be used. Prior to pregnancy, other options such as preimplantation genetic testing are available. It is important to discuss prenatal diagnosis and other options with a physician or genetic counselor before or very early in pregnancy if it is desired. To find a genetic counselor near you, visit the National Society of Genetic Counselors Find a Genetic Counselor website.
Are there other organ specific treatments for cystinosis?
Supportive therapies can be used to treat specific symptoms of cystinosis. A synthetic hormone called L-thyroxine is used to treat hypothyroidism. Growth hormone therapy is used to improve growth. Insulin is used to treat insulin-dependent diabetes. Testosterone supplementation is used to treat hypogonadism in boys. Phosphorous and vitamin D supplementation is used to treat rickets. Carnitine may be given to improve muscle strength. In certain instances, infants and children may have a small tube called a gastronomy tube placed into their abdomen so that they can be given food and other nutrients. This tube is given to infants and children who have difficulty swallowing, have poor nutrition due to feeding difficulties and kidney disease, or are at risk of aspiration, which is when foreign material such as food or fluid accidentally ends up in the lungs.
Are there other names for nephropathic cystinosis?
Cystinosis may also be known as:
Are there late-onset symptoms of cystinosis?
Symptoms in non-nephropathic cystinosis or ocular cystinosis often start in teenagers and adults. Ocular cystinosis primarily affects the eyes, causing bright lights to hurt the eyes (photophobia).
In children with nephropathic and intermediate cystinosis, physicians are learning that these patients can face later onset of new symptoms. Some experience wasting and weakening of muscles. If the muscles in the throat are affected, then swallowing and feeding problems can occur. Children and adults may have an exaggerated gag reflex. If muscles in the lungs are affected, then the lungs may not work as well as they should (pulmonary insufficiency). Gastrointestinal issues including gastroesophageal reflux, inflammatory bowel disease, ulcers, and inflammation of the esophagus can develop. There might be a risk of high blood pressure, hardening of the arteries, and other problems with the heart. Metabolic bone disease, eyelid spasms, eye pain, vision problems, and degenerative changes to the retina have also been reported.
Are there good support groups for cystinosis?
There are several support groups for cystinosis that provide support, information, advice, referrals to physicians and medical centers, and up-to-date information on research and treatments. Support groups for cystinosis include:
Are there any other diseases that look like cystinosis?
Other disorders can cause renal Fanconi syndrome in infancy including Wilson disease, tyrosinemia type I, galactosemia, Lowe syndrome, and glycogen storage disorders. Cystinosis can be mistaken for diabetes insipidus because both disorders cause people to urinate frequently and pass a lot of urine. Bartter syndrome is a group of kidney disorders that are characterized by electrolyte imbalances that are similar to those seen in cystinosis.
Cystinuria is a disorder in which cystine builds up in the urine, causing stones to form that can become stuck in the kidneys, ureter and bladder. Although the names are similar, cystinosis and cystinuria are not related and have completely different symptoms.
Are men with cystinosis sterile?
There have not been any untreated men with cystinosis reported in the medical literature who have fathered a child. Delayed puberty and low testosterone output are common signs of the disorder. Studies have shown that men with cystinosis produce no, or very little sperm, a condition called azoospermia. This is true even for men who begin treatment at an early age. However, there is not a lot of data or research available regarding male fertility and cystinosis.