Spinocerebellar Ataxia Type 37

An autosomal dominant cerebellar ataxia type 1 that is characterized by a cerebellar syndrome along with altered vertical eye movements.

Epidemiology

Spinocerebellar ataxia type 37 (SCA37) has been reported in nine members of a Spanish kindred to date.

Clinical description

Disease onset occurs in adulthood (from the ages of 38-64). Clinical manifestations of SCA37 patients are characterized by slowly progressive cerebellar ataxia (starting with falls, dysarthria and clumsiness followed by other cerebellar signs) along with altered vertical eye movements. Generalized cerebellar atrophy is visible with magnetic resonance imaging.

Etiology

SCA37 is due to a pathogenic pentanucleotide ATTTC insertion within the 1p32 5' non-coding regulatory region of the DAB1 gene (1p32.2).

Diagnostic methods

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

Differential diagnosis includes other types of autosomal dominant cerebellar ataxia.

Antenatal diagnosis

Prenatal diagnosis is not possible.

Genetic counseling

SCA37 is inherited in an autosomal dominant manner and genetic counseling is possible. Genetic counseling should be proposed to individuals having the disease-causing mutation informing them that there is 50% risk of passing the mutation to offspring.

Management and 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.

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.