spinocerebellar ataxia type 37

Overview

Spinocerebellar ataxia type 37 (SCA37) is characterized by adult onset, dysarthria, slowly progressive gait and limb ataxia with severe dysmetria in the lower extremities, mild dysmetria in the upper extremities, dysphagia, and abnormal ocular movements (dysmetric vertical saccades, irregular and slow vertical smooth pursuit, slow vertical optokinetic nystagmus, and oscillopsia (visual disturbance in which objects appear to oscillate). In most individuals, the initial signs/symptoms include falls, dysarthria, or clumsiness followed by a complete cerebellar syndrome. A distinctive clinical feature is the presence of altered vertical eye movements in early stages of the disease, even preceding ataxia symptoms. Clinical progression is slow and affected individuals usually become wheelchair bound between ten and 33 years after disease onset.

Diagnosis

Diagnosis is based on the characteristic clinical findings and molecular genetic testing. As the manifestations of SCA37 are not specific, diagnosis is only confirmed with the finding of a pathogenic mutation in the DAB1 gene.

Differential diagnosis includes other types of autosomal dominant cerebellar ataxia.

Prenatal diagnosis is possible when the ATTTC insertion within the DAB1 gene has been identified in a family member.

Prognosis

Precise prognosis is unknown due to small number of patients reported, but disease progression is slow and the patients generally need wheelchair from 10 and 30 years after the disease onset.

Treatment

There is no cure for SCA37 and treatment is supportive. Physical therapy, as well as the use of canes and walkers, should be offered in order to maximize strength and maintain activity. Wheelchairs are eventually necessary. Speech therapy and communication devices may be useful to those with dysarthria. Annual neurological examinations are recommended to monitor disease progression.