What Are Acanthocytes?
Acanthocytes are abnormal red blood cells with spikes of different lengths and widths unevenly positioned on the cell surface. The name comes from the Greek words “acantha” (which means “thorn”) and “kytos” (which means “cell”).
These unusual cells are associated with both inherited and acquired diseases. But most adults have a small percentage of acanthocytes in their blood.
In this article, we’ll cover what acanthocytes are, how they’re different from echinocytes, and the underlying conditions associated with them.
About acanthocytes: Where they come from and where they’re found
Acanthocytes are thought to result from changes in the proteins and lipids on the red cell surfaces. Exactly how and why the spikes form isn’t fully understood.
Acanthocytes are found in people with the following conditions:
- severe liver disease
- rare neural diseases, such as chorea-acanthocytosis and McLeod syndrome
- abetalipoproteinemia (a rare genetic disease involving an inability to absorb some dietary fats)
- after spleen removal (splenectomy)
- anorexia nervosa
Some medications, such as statins or misoprostol (Cytotec), are associated with acanthocytes.
Acanthocytes are also found in the urine of people with diabetes who have glomerulonephritis, a type of kidney disorder.
Because of their shape, it’s thought that acanthocytes can be trapped and destroyed in the spleen, resulting in hemolytic anemia.
Acanthocytes vs. echinocytes
An acanthocyte is similar to another abnormal red blood cell called an echinocyte. Echinocytes also have spikes on the cell surface, though they’re smaller, regularly shaped, and spaced more evenly on the cell surface.
The name echinocyte comes from the Greek words “echinos” (which means “urchin”) and “kytos” (which means “cell”).
Echinocytes, also called burr cells, are associated with end-stage kidney disease, liver disease, and deficiency of the enzyme pyruvate kinase.
How is acanthocytosis diagnosed?
Acanthocytosis refers to an abnormal presence of acanthocytes in the blood. These misshapen red blood cells can be seen on a peripheral blood smear.
This involves putting a sample of your blood on a glass slide, staining it, and looking at it under a microscope. It’s important to use a fresh blood sample; otherwise, acanthocytes and echinocytes will look alike.
To diagnose any underlying condition associated with acanthocytosis, your doctor will take a full medical history and ask about your symptoms. They’ll also ask about possible inherited conditions and do a physical exam.
In addition to a blood smear, the doctor will order a complete blood count and other tests. If they suspect neural involvement, they may order a brain MRI scan.
Causes and symptoms of acanthocytosis
Some types of acanthocytosis are inherited, while others are acquired.
Hereditary acanthocytosis results from specific gene mutations that are inherited. The gene may be inherited from one parent or both parents.
Here are some specific inherited conditions:
Neuroacanthocytosis refers to acanthocytosis associated with neurological problems. These are very rare, with an estimated prevalence of one to five cases per 1,000,000 population.
These are progressively degenerative conditions, including:
- Chorea-acanthocytosis. This usually appears in your 20s.
- McLeod syndrome. This can appear at ages 25 to 60.
- Huntington’s disease-like 2 (HDL2). This usually appears in young adulthood.
- Pantothenate kinase-associated neurodegeneration (PKAN). This generally appears in children under 10 and progresses rapidly.
The symptoms and the disease progression vary by individual. In general, symptoms include:
- abnormal involuntary movements
- cognitive decline
Some people may also experience psychiatric symptoms.
There isn’t yet a cure for neuroacanthocytosis. But symptoms can be treated. Clinical trials and support organizations for neuroacanthocytosis are available.
Abetalipoproteinemia, also known as Bassen-Kornzweig syndrome, results from inheriting the same gene mutation from both parents. It involves an inability to absorb dietary fats, cholesterol, and fat-soluble vitamins, such as vitamin E.
Abetalipoproteinemia usually occurs in infancy and can be treated with vitamins and other supplements.
Symptoms can include:
- failure to thrive as an infant
- neurological difficulties, such as poor muscle control
- slow intellectual development
- digestive problems, such as diarrhea and foul-smelling stools
- eye problems that get progressively worse
Many clinical conditions are associated with acanthocytosis. The mechanism involved isn’t always understood. Here are some of these conditions:
- Severe liver disease. Acanthocytosis is thought to result from an imbalance of cholesterol and phospholipid on the blood cell membranes. It can be reversed with a liver transplant.
- Spleen removal. Splenectomy is often associated with acanthocytosis.
- Anorexia nervosa. Acanthocytosis occurs in some people with anorexia. It can be reversed with treatment for anorexia.
- Hypothyroidism. An estimated 20 per cent of people with hypothyroidism develop mild acanthocytosis. Acanthocytosis is also associated with severely advanced hypothyroidism (myxedema).
- Myelodysplasia. Some people with this type of blood cancer develop acanthocytosis.
- Spherocytosis. Some people with this hereditary blood disease may develop acanthocytosis.
Other conditions that may involve acanthocytosis are cystic fibrosis, celiac disease, and severe malnutrition.
Acanthocytes are abnormal red blood cells that have irregular spikes on the cell surface. They’re associated with rare inherited conditions as well as more common acquired conditions.
A doctor can make a diagnosis based on symptoms and a peripheral blood smear. Some types of inherited acanthocytosis are progressive and can’t be cured. Acquired acanthocytosis is usually treatable when the underlying condition is treated.
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