GM1 Gangiosidosis is a lysosomal storage disorder characterized by the deficiency of acid beta glucosidase activity and accumulation of GM1 ganglioside, oligosaccharides, and keratan sulfate and its derivatives in all body tissues, especially in the central and peripheral nervous system. The infantile form of this disorder, also known as GM1 gangliosidosis type I, is the most severe form, with an early onset and a rapidly progressive nature. Affected patients typically present with the following features shortly after birth: severe psychomotor and mental retardation, seizures, hepatosplenomegaly, growth retardation, because of a poor appetite and weak suck, hernias, an exaggerated startle response, myopathy, generalized skeletal dysplasia, flexion contractures, coarse facial features, and a tendency towards deafness and blindness. About 50% of children have a macular cherry-red spot, and most patients show respiratory, genitourinary, and integumentary manifestations of the disease. The Maltese population has reported an extremely high incidence of 1 affected child in every 3700 live births. In other populations, the incidence of this condition is unknown; but is estimated to be fairly rare.

GM1 gangliosidosis is caused by mutations in the acid beta galactosidase (GLB1) gene, which encodes the beta galactosidase-1 enzyme.