Gangliosidoses (GM1 and GM2)

GM1 gangliosidosis is due to beta-galactosidase deficiency. The adult-onset form is characterized by progressive generalized dystonia, often associated with akineto-rigid Parkinsonism. Mild skeletal dysplasia and short stature are good diagnostic clues. GM2 gangliosidosis is due to beta-hexosaminidase deficiency. The adult-onset form is characterized by complex neurological disorders, in which features resulting from cerebellar and motor neuron dysfunction are the most frequent. Movement disorders, psychotic symptoms, mild pyramidal signs, axonal polyneuropathy, autonomic dysfunction, and vertical supranuclear palsy can also be observed. Clinical severity and the rate of progression both vary widely from one patient to another. Diagnosis is based on measurements of enzyme activity and molecular analysis. Physiotherapy, speech therapy and management of swallowing are crucial for these patients’ quality of life and prognosis.