Spinocerebellar Ataxias (SCA) are typically inherited in which pattern?

• A. Mitochondrial
• B. Autosomal dominant
• C. Autosomal recessive
• D. X-linked

Answer: (B)

Most spinocerebellar ataxias are inherited in an autosomal dominant pattern. In this mode, a single mutated allele is enough to cause the disease, so you often see affected individuals in multiple generations and both sexes are affected roughly equally. Many SCAs are caused by dominant mutations—often CAG repeat expansions that produce toxic polyglutamine proteins—leading to progressive ataxia across generations, with anticipation sometimes present as the disease starts earlier in successive generations. There are rare autosomal recessive or X-linked ataxias and other forms with different inheritance, but the typical pattern for SCAs is autosomal dominant.