GM1 gangliosidosis

GM1 gangliosidosis is a rare, inherited lysosomal storage disorder caused by a deficiency of the enzyme beta-galactosidase (β-galactosidase), which is encoded by the GLB1 gene located on chromosome 3p22.3. This enzyme deficiency leads to the progressive accumulation of GM1 gangliosides and related glycoconjugates in cells throughout the body, particularly in the central nervous system. The disease is also known as beta-galactosidase-1 deficiency or GLB1-related disorders. It primarily affects the brain and nervous system but also impacts the skeletal system, liver, spleen, and in some forms, the heart. Three clinical subtypes are recognized based on age of onset and severity. Type 1 (infantile form) is the most severe, presenting within the first six months of life with rapid neurodegeneration, hypotonia, hepatosplenomegaly, skeletal abnormalities (dysostosis multiplex), coarse facial features, cherry-red macular spots, and severe intellectual disability, often leading to death by early childhood. Type 2 (late infantile/juvenile form) has a later onset, typically between ages 1 and 5 years, with progressive locomotor difficulties, speech regression, seizures, and cognitive decline. Type 3 (adult/chronic form) presents in late childhood to adulthood with slowly progressive dystonia, gait abnormalities, speech difficulties, and mild vertebral changes, with cognitive function relatively preserved initially but declining over time. Currently, there is no cure or approved disease-specific therapy for GM1 gangliosidosis. Treatment is primarily supportive and symptomatic, including management of seizures, nutritional support, physical therapy, and respiratory care. Several investigational approaches are under active study, including gene therapy, substrate reduction therapy, and pharmacological chaperone therapy. Genetic counseling is recommended for affected families. Diagnosis is confirmed through measurement of beta-galactosidase enzyme activity in leukocytes or fibroblasts and molecular genetic testing of the GLB1 gene.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about GM1 gangliosidosis