What Your Test Results Mean:

Carriers typically show no symptoms of ARSACS; however, carriers are at an increased risk of having a child with ARSACS. Risk for the current or future pregnancies is dependent on your partner’s carrier status. Carrier testing of your partner is recommended in addition to consultation with a genetic counselor for more detailed risk assessment.

Disease Explained:

ARSACS is an inherited neurodegenerative condition in which the pathogenic variants in the SACS gene cause the resulting protein, sacsin, to be unstable. Affected individuals develop gait abnormalities in the first few years of life followed by abnormal muscle contraction, impaired coordination, involuntary eye movements, muscle wasting, and speech difficulties. Most people affected by ARSACS have normal intelligence and live to become independent adults, though eventually they lose their ability to walk and require a wheelchair by the time they reach their thirties or forties.

How the Genetics Works:

ARSACS is an autosomal recessive disorder caused by pathogenic variants in the SACS gene. In general, individuals have two copies of the SACS gene. Carriers of ARSACS have a single variant in one copy of the SACS gene while individuals with ARSACS have variants in both copies of their genes, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.