Sickle-cell anemia

Everyone has two copies of the HBB gene, which codes for a building block of hemoglobin known as beta-globin. Individuals with sickle cell anemia have a change known as hemoglobin S (Hb S) in both of their copies of this gene. When both copies of the beta-globin gene have the Hb S change, the hemoglobin made by that individual is abnormal. This abnormal hemoglobin causes the red blood cells to be abnormally shaped, leading to the various symptoms of sickle cell anemia.

If someone has a family history of sickle cell anemia or other sickle cell diseases, close relatives should be tested for sickle cell and other beta-globin traits. If a close relative has signs or symptoms suspicious for sickle cell anemia, diagnostic testing should be performed even if their newborn screen was normal.

If someone has sickle cell anemia or sickle cell trait and they are concerned about having offspring with sickle cell anemia or other sickle cell diseases, their reproductive partner should be tested for sickle cell and other beta-globin traits. This testing can be coordinated through a general medical practitioner. If the couple desires further discussion about the risks for these disorders in their offspring, they should be referred for a formal genetic counseling session. A genetic counselor could meet with the couple prior to or during a pregnancy to better discuss their offspring’s risk as well as the couple’s reproductive and testing options. To find a nearby genetic counselor, one can search here.

Thanks to improved medical treatments, people with sickle cell anemia and other sickle cell diseases are living longer and longer. Nonetheless, because sickle cell anemia is a chronic condition, it does somewhat shorten a person’s lifespan. Currently, the average lifespan for individuals with sickle cell anemia is over 50 years of age, with women living slightly longer than men.

Although people with sickle cell anemia typically live well into adulthood, complications of their disease can lead to early death. Children who pass away from complications of sickle cell anemia tend to do so for different reasons than adults. The most common causes of death in children with sickle cell anemia are infection and spleen problems. The most common causes of death in adults with sickle cell anemia are organ damage/dysfunction, thrombotic disease (e.g. strokes) and treatment-related complications. Thankfully, as we continue to understand more about how to treat this complex disease, we are finding new ways to prevent or delay these life-threatening complications.

There are several medical specialists that may follow a person with sickle cell anemia. The particular specialists will depend on the symptoms a given affected individual is having at a particular time. Nonetheless, all individuals with sickle cell anemia should be managed by a hematologist, a doctor who specializes in blood diseases. Additional specialists may include:

Abbreviations for sickle cell anemia include:

Sickle cell anemia is an inherited blood disorder. Sickle cell anemia is caused by changes in the gene that helps make hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen to different parts of the body. People with sickle cell anemia have abnormal hemoglobin, causing their red blood cells to be shaped abnormally, sometimes looking like a sickle, or crescent-moon shape. These abnormal red blood cells don’t flow as easily through the blood vessels, causing the flow of blood to slow or stop. This means that oxygenated blood doesn’t get to different tissues in the body as well, leading to symptoms such as pain and organ damage. Additionally, because the blood cells are abnormal and become damaged over time, they are broken down more quickly than normal blood cells. This leads to anemia (low red blood cell counts), which can cause fatigue, or low levels of energy.

There are several complications of sickle cell anemia for which affected individuals should be watched. As a result of vaso-occlusion, or blocked blood vessels, organs can be deprived of oxygen. This can lead to organ damage, most common in the kidneys, liver, spleen, lungs, brain, and eyes.

When kidney damage has occurred, this can lead to problems with urine production. For this reason, some people with sickle cell anemia can have uncontrolled urination, and in some cases, bedwetting. Blood and/or protein in the urine is another concerning sign of kidney damage. Your doctor can monitor for these complications.

Your doctor can monitor for the following signs of liver damage: clay-colored or white stools, dark urine, uncontrollable itching, nausea/vomiting, and pain in the right upper part of the abdomen.

When the spleen has been damaged, it cannot help fight bacterial infections as well as it usually does. Your doctor should look for warning signs including frequent infections and enlarged spleen.

If the vessels leading to the lungs have been blocked for a prolonged amount of time, this can lead to "acute chest syndrome". Symptoms of this include: chest pain, fever, shortness of breath, rapid breathing and cough. This is a serious complication of sickle cell anemia for which affected individuals should be monitored.

Another serious complication occurs if there is damage to brain cells. This can lead to symptoms that are similar to those of someone who have had a stroke. When this occurs in a person with sickle cell anemia it is known as a "clinical stroke" because although there was not an actual stroke, the damage to the brain leads to similar outward signs. Signs of clinical stroke include: one-sided arm/leg weakness, trouble speaking, difficulty walking, trouble understanding, loss of balance and severe headache.

When the eye has been damaged due to oxygen deprivation as a result of sickle cell anemia, this can lead to the retina detaching. A warning sign for which affected individuals should be monitored is vision impairment or loss.

Apart from complications due to organ damage, there are other concerns related to sickle cell anemia for which doctors should watch. These include: leg ulcers, swollen joints, delayed growth, pregnancy complications and mental health problems.

Sickle cell anemia is caused by a change in the beta-globin gene, which is known as HBB. HBB codes for beta-globin, one of the building blocks of hemoglobin. The specific change in the gene that causes sickle cell anemia is known as the hemoglobin S, or Hb S, mutation.

Sickle cell anemia is associated with many physical symptoms. The most common symptom is pain. Some individuals with sickle cell anemia have chronic pain, the cause of which is not well understood. There are also acute events of pain which can come on without warning. This results from the abnormally shaped red blood cells blocking blood vessels and is known as "vaso-occlusive pain". Episodes of vaso-occlusive pain are known as "sickle cell crises". The most common sites for these pain crises are the lower back, legs, arms, abdomen and chest.

Other common symptoms of sickle cell anemia include shortness of breath, extreme fatigue, dizziness and pale skin. These are the result of the anemia that occurs in sickle cell anemia as a result of the rapid breakdown of the abnormal red blood cells.

Finally, it is common for individuals with sickle cell anemia to have frequent infections, inflamed fingers or toes known as "sickle cell dactylitis", yellow-colored eyeballs ("scleral icterus") and swollen hands or feet.

Chronic pain is one of the most difficult symptoms of sickle cell anemia. It can take a toll on a person’s mental and physical well-being. Managing pain is something that should be done between the patient and his or her managing doctor. Typical pain management regiments may include hydration, over-the-counter pain medications, prescription pain medications, physical therapy, acupuncture, and home remedies such as heating pads, warm baths, self-hypnosis and massage.

All states in the United States do newborn testing for sickle cell anemia. Sickle cell anemia is on the recommended uniform screening panel (RUSP) states use to decided which tests are important to add to their state newborn screening testing.

It should be noted that newborn screening can have false positives and false negatives. Therefore, follow-up testing is recommended to confirm the diagnosis in infants with positive newborn screen results. Furthermore, if any person is suspected of having sickle cell anemia, even if the newborn screen was normal, diagnostic testing should be performed.

There are several tests that can diagnose sickle cell anemia. These tests rely on identifying the presence of the abnormal hemoglobin S and/or sickle- or otherwise abnormally-shaped red blood cells. Diagnostic tests for sickle cell anemia include: hemoglobin electrophoresis, isoelectric focusing, high-performance liquid chromatography, and/or a peripheral blood smear. Although it is possible to diagnose sickle cell anemia through genetic testing looking for two copies of the Hb S gene change, this is an expensive method and therefore is rarely performed. Genetic diagnosis of sickle cell anemia is typically reserved for prenatal diagnosis.

An older test, known as a sickle cell solubility test (also known as a Sickledex), is no longer recommended for several reasons. First, it does not differentiate between sickle cell trait and sickle cell disease. Secondly, false negatives and false positives have been reported. Lastly, it cannot diagnose or rule out sickle cell diseases other than sickle cell anemia, such as sickle-hemoglobin C disease.

Although a relatively rare disease, sickle cell anemia and other sickle cell diseases are some of the most common blood disorders worldwide. Therefore, there are many researchers interested in studying the disease in order to better understand how to manage, treat, or cure it. As of May 2016, there are over 180 open studies looking at sickle cell diseases on clinicaltrials.gov. Many of these studies are focusing on specific symptoms of sickle cell diseases, such as respiratory, cardiac, or liver complications.

There are also several drugs and other treatments under investigation for sickle cell anemia. These include regadenoson, a medication that may prevent the inflammation and injury caused by the sickle shaped cells, various pain medications to manage the crises in affected individuals, and gene therapy, looking to increase production of normal hemoglobin.

The field of sickle cell anemia treatment research is a rapidly changing field. In order to learn more about the most up-to-date research opportunities, please check [link url="clinicaltrials.gov” target=”_blank”>this site for updates.

There are several medications and procedures used to treat the symptoms for the disease. An important part of treated sickle cell anemia is staying healthy by getting proper nutrition, having good sleep habits, and getting all vaccines including annual flu shots. When a pain crisis occurs, pain management with pain relieving medications is important. Individuals with sickle cell anemia who become severely anemic or will need periodic blood transfusions, which can also help reduce the risk of a stroke. There is one FDA approved medication, hydroxyurea (Hydrea or Droxia) made by Bristol-Myers Squibb Company for the treatment of sickle cell disease. Hydroxyurea helps stimulate the production of fetal hemoglobin and decrease the severity of disease symptoms.

Currently, the only cure for sickle cell anemia is a hematopoietic stem cell transplant (HSCT). Stem cells are cells that, as they divide and divide, have the ability to become many different types of cells. Hematopoietic stem cells are cells that, after many cell divisions, can become the different types of cells that make up blood: red blood cells, white blood cells, and platelets.

HSCT involves receiving a bone marrow transplant from someone that has healthy, non-sickled red blood cells. The bone marrow donor is typically a close relative to the individual with sickle cell anemia, such as a healthy sibling or parent. The donor may not have sickle cell anemia or another sickle cell disease but may have sickle cell trait.

Before the individual receives the bone marrow transplant, he or she must first be treated with agents that kill off their own bone marrow cells. The individual is then injected with the healthy donor bone marrow. Over time, the goal is for the healthy bone marrow cells to take over red blood cell production for that person, hopefully eliminating production of the diseased, sickled red blood cells, essentially providing a cure for the disease.

Currently, HSCT is reserved for those individuals with the most severe complications of sickle cell anemia. Additionally, because the treatment is riskier in adults, it is typically only used on children with sickle cell anemia. Only about 10% of individuals with sickle cell anemia have a related matched bone marrow donor; therefore, most people with sickle cell anemia are not candidates for HSCT. In those who receive HSCT from a related matched donor, the process is successful about 85% of the time.

Women with sickle cell anemia can have children; however, because of the mother’s underlying disease, the pregnancies are inherently higher risk. All such pregnancies should be managed by an obstetrician (often a high-risk provider known as a Maternal-Fetal Medicine physician) as well as a hematologist. Pregnant women with sickle cell anemia have an increased risk of blood clots ("thrombosis"), infections and pain crises. There is also some data to suggest an increased risk for pre-term labor, preeclampsia, eclampsia and maternal death. If a woman is using hydroxyurea to treat her sickle cell anemia, she should discontinue this during pregnancy, as there are concerns it can increase the chance of birth defects in exposed babies.

If a pregnancy is thought to be at risk for sickle cell anemia or other sickle cell diseases, it is possible to have a test to determine if the baby will have the disease or not. It is first important, however, to know whether both parents have sickle cell or another beta-globin trait. This is important not only to determine the risk for sickle cell anemia or sickle cell disease in the fetus, but also because the specific testing performed will depend on what gene changes each parent carries. In some cases, the father is unavailable or unwilling to be tested but the mother knows that she has sickle cell trait. In this case, it is important to meet with a genetic counselor to discuss the potential risks to your baby as well as what testing options exist. Your obstetrician can refer you to a genetic counselor, or you can find one here.

Once the carrier status of both parents of a pregnancy are known, the genetic counselor can help discuss the benefits, risks and limitations of prenatal testing for sickle cell anemia. The genetic counselor can also help coordinate this testing and make sure results are given out in a timely, accurate manner. If a person knows that they offspring are at risk for sickle cell anemia and other sickle cell diseases because he or she is a carrier of sickle cell trait, it might also be helpful to arrange a genetic counseling visit before becoming pregnant to discuss these emotional and anxiety-laden issues at the earliest stage possible.

Although the features of sickle cell anemia vary from one affected individual to the next, all individuals with two copies of the Hb S gene change will have symptoms of sickle cell anemia.

Sickle cell anemia runs in families in an autosomal recessive pattern. This means that in order to have sickle cell anemia, the abnormal hemoglobin S gene must be passed on by both parents. If the abnormal hemoglobin S gene is inherited from only one parent and a normal hemoglobin gene is inherited from the other, a person will have sickle cell trait and not be affected by sickle cell anemia. If both parents have sickle cell trait (meaning, one abnormal hemoglobin S gene and one normal beta-globin gene), there is a 25% change with each pregnancy that the baby will be affected by sickle cell anemia, a 50% chance that the baby will have sickle cell trait (which in most case not cause any disease symptoms), and a 25% change that the baby will inherit the normal hemoglobin genes from each parent and not have disease or trait. If one parent has sickle cell anemia and the other has sickle cell trait, each pregnancy is at 50% risk to be affected with sickle cell anemia and 50% risk to be an unaffected carrier of sickle cell trait.

There are several non-profit groups that work towards increasing awareness of sickle cell anemia as well as raising funds to support disease research. The following are organizations within the U.S. to which interested individuals can donate: American Sickle Cell Anemia Association and Sickle Cell Disease Association of America.

The National Organization for Rare Disorders (NORD) is a patient advocacy organization dedicated to individuals with rare diseases and the organizations that serve them. Donations to NORD can be made here.

Sickle cell anemia can be diagnosed with simple blood tests. In the United States, the most common way people are first suspected as having sickle cell anemia is through newborn screening. However, newborn screening cannot tell for certain if a person has sickle cell anemia. The best way to diagnose sickle cell anemia is through simple blood tests looking for the presence of hemoglobin S and/or sickle- and other abnormally-shaped red blood cells. This can be done through several different tests. These tests for sickle cell anemia can be done by any medical care provider and do not require coordination through a specialist such as a geneticist or hematologist.

The field of sickle cell anemia research is a rapidly changing field. In order to learn more about the most up-to-date research opportunities, please check [link url="clinicaltrials.gov” target=”_blank”>this site for updates. You can also search pharmaceutical companies’ sites for ongoing drug trials. For example, as of May 2016, there are two drug trials at the Pfizer pharmaceutical company in regards to sickle cell anemia.

As of May 2016 there are 10 NIH-designated Centers of Excellence in Sickle Cell Anemia. They can be found here. At this time the following centers have this designation:

Sickle cell anemia is the most common inherited blood disorder in the U.S. It affects up to 100,000 people in the U.S. and hundreds of thousands worldwide. It is most common in individuals with African, Asian Indian, Middle Eastern, Greek, Italian or Mediterranean ancestry, but can affect people of any ethnic background.

Because sickle cell anemia is a chronic, lifelong disease, it can often feel overwhelming and stressful to cope with it on a daily basis. It is normal to feel tired and sad about never getting a break from the complications of the disease. Depression is very common in people with sickle cell anemia and can be treated with therapy and/or medicine. It is important that people with sickle cell anemia take good care of their mental well-being, because people with uncontrolled mental health problems are at risk for increased physical symptoms of sickle cell anemia. You can ask your doctor for a referral to a mental health professional. You might also consider joining an online or in-person support group as a way to help deal with your feelings.

The symptoms of sickle cell anemia can be made worse by the following:

Because sickle cell anemia does not typically affect the way a person thinks or learns, children with sickle cell anemia and other sickle cell diseases can attend regular classrooms. Nonetheless, because they often have recurrent illnesses that may require staying home from school and/or hospitalizations, they may struggle somewhat to keep up with their classmates. There are things that teachers and other school staff can do to support children with sickle cell anemia to help them have the best education possible while decreasing their chance of additional medical complications. These include:

Sickle cell anemia is also known as:

Sickle cell anemia belongs to a group of disorders known as sickle cell disease. They differ from one another based on the specific gene changes an individual has in the beta-globin gene; however, their symptoms can overlap. Other sickle cell diseases such as sickle-hemoglobin C and hemoglobin S-beta thalassemia tend to be milder conditions that sickle cell anemia. They can easily be differentiated from one another through simple blood tests such as hemoglobin electrophoresis.

There are several support organizations devoted to helping people and families who have sickle cell anemia and related sickle cell diseases. The two largest such organizations in the U.S. are The American Sickle Cell Anemia Association and the Sickle Cell Disease Association of America.

Because sickle cell anemia and related sickle cell diseases are relatively common, there are often local chapters that belong to larger sickle cell anemia support organizations. Affected individuals and their families can get involved with and seek support from both national- and local-level groups. A list of some of the local chapters can be found here and here.