Is Chorea-acanthocytosis ChAc hereditary?

Chorea-acanthocytosis (ChAc) is a rare, hereditary genetic disorder caused by mutations in the VPS13A gene. It follows an autosomal recessive inheritance pattern, meaning an individual must inherit two copies of the mutated gene—one from each parent—to develop the condition.

Is Chorea-acanthocytosis (ChAc) hereditary?

Yes, Chorea-acanthocytosis (ChAc) is strictly hereditary. It is not a multifactorial or spontaneous condition; it is caused by specific pathogenic variants in the VPS13A gene located on chromosome 9. Because it is autosomal recessive, parents of an affected individual are typically asymptomatic carriers who each carry one mutated copy of the gene.

What is the risk of inheritance for family members?

When both parents are carriers of the Chorea-acanthocytosis (ChAc) mutation, the risks for each pregnancy are as follows:

• 25% chance that the child will inherit two mutated copies and develop Chorea-acanthocytosis (ChAc).


• 50% chance that the child will be an asymptomatic carrier like the parents.


• 25% chance that the child will inherit two normal copies of the gene and be neither affected nor a carrier.

How is Chorea-acanthocytosis (ChAc) diagnosed genetically?

Genetic testing for Chorea-acanthocytosis (ChAc) involves molecular analysis of the VPS13A gene. This is recommended when clinical symptoms—such as chorea, dystonia, or the presence of acanthocytes (spiky red blood cells) in the blood—are observed. De novo (spontaneous) mutations are extremely rare in Chorea-acanthocytosis (ChAc); therefore, the diagnosis almost always implies a family history of carrier status.

What is the role of genetic counseling?

Genetic counseling is essential for families affected by Chorea-acanthocytosis (ChAc). Counselors help interpret complex test results, facilitate carrier testing for siblings or extended family members, and discuss reproductive options, such as preimplantation genetic testing (PGT) or prenatal diagnosis, for those planning pregnancies.

Next steps

• Consult a board-certified clinical geneticist to discuss diagnostic testing and family screening.


• Connect with the 6 members of the Chorea-acanthocytosis (ChAc) community at DiseaseMaps.org for peer support.


• Request a referral to a movement disorder specialist experienced in rare neuroacanthocytosis syndromes.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Chorea-acanthocytosis


• Orphanet: Chorea-acanthocytosis (ORPHA:167)


• OMIM (Online Mendelian Inheritance in Man): #200150 CHOREA-ACANTHOCYTOSIS


• National Institute of Neurological Disorders and Stroke (NINDS): Neuroacanthocytosis information