Juvenile-onset G(M2)-gangliosidosis in an African-American child with nystagmus.

G(M2)-gangliosidosis is a neurodegenerative lysosomal disease with several clinical variants. We describe a 2-year-old black child with juvenile-onset disease, who presented with abnormal eye movements and cherry-red spots of the maculae. Mutation analysis of the HEXA gene revealed the patient to be a compound heterozygote (M1V/Y37N). The M1V mutation was previously described in an African-American child with acute infantile G(M2)-gangliosidosis. The Y37N mutation is novel. This combination of mutations is consistent with juvenile-onset disease, and provides further evidence for the association of the M1V mutation with individuals of black ancestry. The presence of oculomotor abnormalities is an unusual finding in this form of G(M2)-gangliosidosis, and adds to the phenotypic spectrum.