Why do individuals with spinocerebellar ataxia experience loss of muscle control, even though the ataxin-1 protein builds up only in the brain and spinal cord? O A Inclusions can build up in all body systems and can cause debilitating effects. OB. Genetic mutations in the ataxin-1 protein cause muscular proteins to change shape. OC. When the ubiquitin tagging system does not work effectively, cellular waste can build up in the muscles. OD. The neurons affected by the ataxin-1 protein buildup are in a region of the brain that manages muscle control.​