Two unrelated children and their siblings of Arab origin were diagnosed as having GM1 gangliosidosis on the basis of clinical features and markedly low levels of beta-galactosidase. The T2-weighted magnetic resonance images of the brain revealed certain characteristic features, including delayed myelination and abnormal appearance of the subcortical white matter, internal capsule, and basal ganglia. Their mutation analysis showed two novel mutations, which have not been described in an Arabic population.