Mild Canavan Disease

Mild Canavan disease (CD) is a neurodegenerative disorder characterized by mild speech delay or motor development.

Epidemiology

Mild CD has been identified in only a few cases. The majority of patients with Canavan disease have the severe form (see this term). In contrast to the severe CD, most mild CD patients are not from Ashkenazi Jewish descent.

Clinical description

Mild CD usually presents in childhood with mild developmental delay or problems with speech or motor development. Head circumference is usually normal. Retinitis pigmentosa (see this term) may be present. .

Etiology

CD is caused by mutation in the ASPA gene (17p13.3), coding for the aspartoacylase enzyme. Mild CD is associated with heterozygous genotypes comprising a mild mutation and a severe one. Mild mutations include Y288C, R71H, P257R, I143T, and Y231C.

Diagnostic methods

The brain MRI usually demonstrates an increased signal intensity in the basal ganglia and the urine level of N-acetyl-L-aspartic acid (NAA) is slightly elevated. Mutation screening can be performed for molecular diagnosis.

Prognosis

Prognosis is good and children often attend normal school but may need speech therapy or a tutor. Life expectancy is normal.