ATXN1 (Ataxin 1): ATXN1 is a gene that encodes the ataxin-1 protein, which plays a role in neuronal function. Mutations in ATXN1, especially those involving expanded CAG repeats, lead to spinocerebellar ataxia type 1 (SCA1) — a neurodegenerative disorder marked by progressive loss of motor coordination and balance. Studying ATXN1 is important for understanding SCA1 and developing potential treatments for related neurological diseases.