What are neuroacanthocytosis syndromes?
Neuroacanthocytosis syndromes are a group of nervous system conditions that cause unintended (involuntary) muscle movements. People with these conditions often have irregularly shaped red blood cells (acanthocytosis).
Neuroacanthocytosis syndromes get worse over time and don’t currently have a cure. People may develop symptoms throughout life, depending on the type of neuroacanthocytosis they have. However, most people with neuroacanthocytosis syndromes develop symptoms as adults.
Variants (also called mutations) in a small group of specific genes cause neuroacanthocytosis syndromes. The syndromes can affect many parts of the brain and nervous system. The most common types of neuroacanthocytosis cause damage to the part of the brain that controls movement.
Symptoms of neuroacanthocytosis syndromes
Different neuroacanthocytosis syndromes can cause different symptoms, but some common ones include:
Types of neuroacanthocytosis syndromes
Many different types of neuroacanthocytosis exist, including the following:
VPS13A disease
Some people with VPS13A disease, which usually appears in adulthood, don’t experience uncontrolled, dance-like muscle or facial movements (chorea) or irregularly shaped red blood cells. But they can have other symptoms, such as biting the tongue or lips.
VPS13A disease is caused by variants in the VPS13A gene that makes the protein chorein, which is thought to be involved in nerve or brain cell damage.
VPS13A disease is autosomal, meaning the gene variants that cause it are located on non-sex chromosomes. VPS13A disease is inherited in an autosomal recessive pattern. This means a person must inherit two copies of the affected gene, one from each parent, to have the disease. The parents of a person with an autosomal recessive condition each carry one copy of the altered gene, but they typically don’t show signs and symptoms of the condition.
McLeod syndrome (or XK disease)
McLeod syndrome, which typically appears in middle age, can cause serious heart problems.
McLeod syndrome is caused by variants in the XK gene on the X chromosome. The XK gene makes a protein on the surface of red blood cells. For this reason, blood transfusions can be dangerous for people with McLeod syndrome because of differences in XK on their red blood cells.
McLeod syndrome is sex-linked, meaning the gene variants that cause it are located on sex chromosomes (X or Y chromosomes). McLeod syndrome is inherited in an X-linked pattern. This means a person inherits the condition from the X chromosome.
Males are more likely to be affected by X-linked conditions like McLeod syndrome, since they usually only inherit a single X chromosome. But in rare cases, women may also show symptoms of McLeod syndrome.
Huntington disease-like 2
Huntington disease-like 2 (HDL2) is very similar to Huntington’s disease. People with HDL2 may have rigid muscles and uncontrolled movements. Most people start to experience HDL2 symptoms around middle age and symptoms get worse over time.
HDL2 is caused by variants in the JPH3 gene that makes a protein involved in brain cell communication. People with African ancestry are more likely to have these variants in the JPH3 gene and are, thus, at higher risk for this disease.
HDL2 is autosomal, meaning the gene variants that cause it are on non-sex chromosomes. HDL2 is inherited in an autosomal dominant pattern. In these cases, a person only needs to inherit one copy of the affected gene from either parent to have the disease.
Like Huntington’s disease, HDL2 belongs to a group of genetic disorders that happen when parts of a person’s DNA are repeated many times, which can disrupt function of the JPH3 protein.
Who is more likely to get neuroacanthocytosis syndromes?
Neuroacanthocytosis syndromes can be passed from parents to children in many ways. For this reason, people are more likely to get neuroacanthocytosis depending on the type of neuroacanthocytosis they have and the way it is inherited.
For all types of neuroacanthocytosis, people with family members who have some type of neuroacanthocytosis are more likely to have this condition. If you think someone in your family may have a neuroacanthocytosis syndrome or that you might be a carrier, let your medical team know, and they may refer you for genetic testing.
How are neuroacanthocytosis syndromes diagnosed and treated?
Diagnosing neuroacanthocytosis syndromes
Doctors usually diagnose neuroacanthocytosis syndromes based on:
- Symptoms and observations by a doctor
- Family history
- Laboratory and imaging tests
In most cases, doctors use genetic testing to confirm a neuroacanthocytosis syndrome diagnosis. Gene testing can identify the type of neuroacanthocytosis.
Learn more about neurological diagnostic tests and procedures.
Treating neuroacanthocytosis syndromes
Neuroacanthocytosis syndromes get worse over time, and no treatments are currently available to prevent or slow their progression. Treatment for people with these conditions typically involves managing symptoms and improving a person’s ability to perform daily tasks.
Medicines like botulinum toxin injections may help with movement disorder symptoms by preventing uncontrolled movements of the body and face. Some medicines can help prevent seizures, and others may help address psychiatric conditions, such as depression or anxiety.
Medical devices, such as feeding tubes or pacemakers, can help people with specific symptoms. Speech, occupational, and physical therapy may also be helpful.
What are the latest updates on neuroacanthocytosis syndromes?
The National Institutes of Health (NIH), which includes NINDS, is the leading federal funder of research on the brain and nervous system, including disorders such as neuroacanthocytosis syndromes. NIH supports new and innovative research to better understand, diagnose, and treat neuroacanthocytosis syndromes.
For more information on research about neuroacanthocytosis syndromes, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.
For research articles and summaries on neuroacanthocytosis syndromes, search PubMed, which contains citations from medical journals and other sites.
How can I or my loved one help improve care for people with neuroacanthocytosis?
Consider participating in a clinical trial so clinicians and scientists can learn more about neuroacanthocytosis syndromes and related disorders. Clinical research with human study participants helps researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of participants are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities. This helps make sure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who will use them.
For information about participating in clinical research, visit the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with neuroacanthocytosis syndromes at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.
Where can I find more information about neuroacanthocytosis?
Information may be available from the following sources: