Hereditary Spherocytosis

Hereditary spherocytosis (HS) is an inherited blood disorder that causes hemolytic anemia. Hemolytic anemia is a term that describes the premature breakdown of red blood cells. With this condition, you’re born with abnormal genes (variants) that cause your red blood cells to lose their usual disk-like shape. They become round or spherical cells (spherocytes) that break down too fast.

It can affect people of all ages. But since it’s something you’re born with, most people get diagnosed as babies or children. If the anemia is mild, you may be diagnosed in adulthood.

There’s no cure, but treatments can manage it. Most people have mild to moderate disease, with symptoms like those of anemia. Rarely, hereditary spherocytosis can be life-threatening. Even then, there are treatments that can help.

Symptoms of hereditary spherocytosis

Symptoms depend on how severe the disease is. The most common ones are the same as in anemia. They include:

• Fatigue
• Fast heartbeat
• Pale skin
• Shortness of breath

Other symptoms happen when HS leads to other conditions, like:

• Gallstones: Too much bilirubin in your blood can form stones in your gallbladder or bile ducts. Bilirubin is a waste product of red blood cells when they break down. Gallstone symptoms include nausea and pain in your upper abdomen.
• Neonatal jaundice: In newborns, too much bilirubin can lead to jaundice. Signs include yellowy eyes, skin and mucous membranes.
• Enlarged spleen: You may have an enlarged spleen. Your spleen filters out old and damaged red blood cells. But with HS, the sphere-shaped cells can get trapped inside. Your spleen may stretch to make room. This can lead to pain in your upper left abdomen (where your spleen is).

Hereditary spherocytosis causes

Abnormal genes (variants) cause it. You inherit the variant from one or both biological parents. Experts have found five gene variants that cause hereditary spherocytosis.

The normal forms of these genes allow your red blood cells to make proteins that support their membranes. This allows red blood cells to twist and turn as they squeeze through narrow blood vessels. After they pass through, they return to their usual shape — a bi-concave disk.

In hereditary spherocytosis, the variants prevent the membrane from being flexible and strong. Instead of flexible disks, red blood cells become rigid spheres. Bits and pieces can break off when they try to squeeze through blood vessels. Your spleen destroys the spherocytes, removing them from your blood.

Inheritance

There are two possible patterns of inheritance that lead to this condition. They are:

• Autosomal dominant: Hereditary spherocytosis is most commonly inherited in an autosomal dominant pattern. This means a child needs to inherit only one altered gene copy from one parent to develop the condition. This occurs in about 3 out of 4 cases.
• Autosomal recessive: Less commonly, hereditary spherocytosis can be inherited in an autosomal recessive pattern (about 1 in 4 cases). Both parents carry one copy of a mutated gene and pass it along to the affected child. But they typically don’t show symptoms themselves.

Risk factors

Since this condition is genetic, it affects certain groups more than others. For example, HS affects about 1 in 20,000 individuals of Northern European ancestry. This makes it the most common cause of an inherited chronic hemolytic anemia in Northern Europe and North America. It’s a less common cause of hemolysis (early blood cell destruction) in African American and Southeast Asian populations.

How doctors diagnose this condition

Healthcare providers consider your symptoms and ask questions about your family’s medical history. They may suspect HS if it runs in your family.

They’ll also order blood tests, which may include:

• Complete blood count: Lets providers know if your body is making enough normal red blood cells
• Peripheral blood smear: Can show if you have spherocytes
• Coombs test: Helps rule out other types of hemolytic anemia
• Hemolysis tests: Detect signs of red blood cell destruction, like high bilirubin and lots of immature red blood cells
• Red cell osmotic fragility: Reveals whether red blood cells are likely to break down
• Band 3 protein testing: Measures the amount of a protein on the surface of red blood cells that helps maintain the cell’s normal shape and function
• Genetic testing: Shows if you have one of the five common gene variants

At what age do doctors diagnose hereditary spherocytosis?

Healthcare providers typically diagnose hereditary spherocytosis in infants and young children. Infants with severe anemia often get blood tests about a week after being born.

But you may not get diagnosed until you’re an adult, especially if you have a mild form of the disease.

How is it treated?

There’s no cure for HS. But treatments manage the condition by reducing symptoms and preventing complications. Options include:

• Blood transfusions: You or your child may need red blood cells from a donor to treat severe anemia.
• Erythropoietin-stimulating agents (ESA): This medicine helps your body make red blood cells. Newborns with severe anemia may get ESA alone or along with blood transfusions as soon as they’re diagnosed.
• Folate supplements: Folate helps your body make red blood cells.
• Phototherapy: This treatment uses light to treat jaundice in newborns.
• Splenectomy: This surgery removes all or part of your spleen.

A splenectomy can ease anemia symptoms. But living without a spleen may make it harder for your body to fight infections. Your provider will help you weigh the benefits versus the risks if spleen removal is an option.

When should I see my healthcare provider?

Your provider will tell you how often you’ll need checkups. During these visits, they’ll check your red blood cell counts. They’ll look for signs of complications, like gallstones or an enlarged spleen.

What can I expect if I have this condition?

Most people have a good prognosis, or outlook. Hereditary spherocytosis doesn’t usually lead to a reduced life expectancy or quality of life.

Still, your situation depends on your symptoms, overall health and response to treatment.

Your healthcare provider will explain what to expect based on your case.

Is there anything I can do to feel better?

It’s always important to follow the care plan you and your healthcare provider decide. You should also feel free to ask about the routine things you can do to manage your condition. For example, your provider can ensure you’re getting the daily nutrition needed to support red blood cells, like iron and folate. They can recommend activities that keep you in good shape without stressing your body.

Can this be prevented?

You can’t change the genes you’re born with. But remember that having a family history of hereditary spherocytosis only increases your chances of developing it. There’s no guarantee that you will or won’t have HS.

If you’re concerned about the risks, see a genetic counselor. They can help you decide whether you or your family members need tests to check for the genes that cause the disease.