Spinocerebellar ataxia (SCA) is a group of inherited brain disorders that affect the cerebellum, a part of the brain vital to physical movement. SCA comprises more than 40 types of similar inherited brain disorders. It causes problems with coordination and movement, which worsen over time. SCA is an autosomal dominant disease, meaning that it takes only one copy of the mutated gene from one biological parent to cause the condition. Therefore, when a person with SCA has children, each child has a 50% chance of inheriting the mutated gene. There are also autosomal recessive spinocerebellar ataxias. In these cases, a person inherits an abnormal gene from both biological parents, who are generally asymptomatic.

SCA is a rare disease, and to date, more than 40 distinct genetic SCAs have been identified, which are classified according to the genetic loci in order of identification. SCA1 was the first SCA described, and then further subtypes are identified sequentially. SCA doesnt compulsorily mean that it is restricted to the cerebellum and spinal cord. It may involve other parts of the central nervous system as well, such as pontine nuclei, spinal cord, peripheral nerves, cortex, basal ganglia, etc. .

It is important to note that "SCA" can also stand for "sudden cardiac arrest," which is a condition in which the heart suddenly stops beating. However, in the context of the search results provided, "SCA" refers to "spinocerebellar ataxia."