GM1-Gangliosidosis, type 2 is a lysosomal storage disorder characterized by the accumulation of acidic lipid materials such as GM1 ganglioside, oligosaccharides, and the mucopolysaccharide keratan sulfate in the neurons of the central and peripheral nervous systems, resulting in the progressive destruction of these neurons. Patients suffer from developmental regression, progressive psychomotor retardation, ataxia, seizures and dementia. GM1-Gangliosidosis has three subtypes based on age of onset: type 1 is the severe infantile form of the disorder affecting children at birth or in early infancy, type 2 is the milder form and has a juvenile or late-infantile onset, usually presenting in children aged 1-3 years, while type 3 is the mildest subset, also known as the adult or chronic form of the disorder.
While GM1-Gangliosidosis has an estimated prevalence of about 1 in 100,000 to 200,000 live births, type 2 is the less frequent form, with only about 50 cases reported so far. GM1-Gangliosidosis, Type II follows an autosomal recessive pattern of inheritance and is caused by mutations in the GLB1 gene.