Spinocerebellar ataxia 4 (SCA4) is a very rare form of hereditary progressive movement disorder. Symptoms include muscle weakness (atrophy) and difficulty coordinating body movements (ataxia), most notably causing a jerky, unsteady walking style (gait) and difficulty speaking (dysarthria). A distinctive feature of SCA4 is the progressive loss of feeling or sensation in the hands and feet (peripheral neuropathy) and loss of reflexes. SCA4 is inherited in an autosomal dominant manner. Although SCA4 has been linked to a location on chromosome 16, (16q22.1), the gene which causes SCA4 when mutated has not been found. Diagnosis is based on symptoms consistent with the disease.