Spinocerebellar Ataxia Type 29
An autosomal dominant cerebellar ataxia type I that is characterized by very slowly progressive or non-progressive ataxia, dysarthria, oculomotor abnormalities and intellectual disability.
Epidemiology
Spinocerebellar ataxia type 29 (SCA29) prevalence is unknown. More than 50 cases have been reported in the literature to date.
Clinical description
SCA29 presents at birth, or shortly after, with manifestations including very slowly progressive or non-progressive gait and limb ataxia causing delayed walking and frequent falling in children. Mild developmental delay, learning difficulties, and language dysfunction are frequently reported. Other manifestations include nystagmus, dysarthria, dysmetria, and dysdiadochokinesia. Affected patients occasionally present with intention tremor, dystonia, and migraine headaches. Although the disease course is not well established, it appears to range from non-progressive or very slowly progressive ataxia (that does not affect ambulation) to progressively disabling ataxia. A slight improvement in cerebellar signs has been reported in some cases over time.
Etiology
SCA29 is due to mutations in the ITPR1 gene (3p26.1), which is also the causal gene of SCA15.
Diagnostic methods
Diagnosis is based on the characteristic clinical findings and molecular genetic testing. As the manifestations of SCA29 are not specific, diagnosis is only confirmed with the finding of a mutation in the ITPR1 gene.
Differential diagnosis
Differential diagnosis includes other types of autosomal dominant cerebellar ataxia.
Antenatal diagnosis
Antenatal diagnosis is possible in families with a known mutation.
Genetic counseling
SCA29 is inherited autosomal dominantly, occasionally autosomal recessively, and genetic counseling is possible.
Management and treatment
There is no cure for SCA29 and treatment is supportive. Annual neurological examinations are recommended to monitor disease progression.
Prognosis
Disease progression is very slow, but precise prognosis is unknown.