What causes spinocerebellar ataxia?

Spinocerebellar ataxia (SCA) is caused by genetic mutations in genes that encode proteins involved in various cellular processes, such as neuronal development, RNA processing, and protein degradation.

Each type of SCA is linked to a specific gene mutation:

SCA1: Caused by an expanded CAG (cytosine-adenine-guanine) repeat in the ATXN1 gene, leading to the production of an abnormal form of the ATXIN1 protein.

SCA2: Caused by an expanded CAG repeat in the ATXN2 gene, resulting in the formation of a toxic protein that affects the normal function of the brain and spinal cord.

SCA3: Also known as Machado-Joseph disease, caused by an expanded CAG repeat in the ATXN3 gene, impacting neural development and causing progressive neurological symptoms.

SCA6: Caused by mutations in the CACNA1A gene, which encodes a calcium channel involved in regulating nerve cell communication.

SCA7: Associated with mutations in the ATXN7 gene, primarily affecting the coordination and balance of individuals.

SCA8: Caused by mutations in the ATXN8 gene, leading to impaired protein degradation and progressive neurological dysfunction.

It's important to note that there are several other subtypes of SCA with varying genetic causes. Furthermore, some cases of SCA can be inherited in an autosomal dominant manner (requiring only one copy of the mutated gene) while others follow an autosomal recessive inheritance pattern (requiring two copies of the mutated gene). Genetic testing can identify the specific cause of SCA in a person or family and provide prognostic and treatment information.