Retrospective Diagnosis of GM1 Gangliosidosis by Use of a Newborn-Screening Card

A deficiency of lysosomal β-d-galactosidase (βG; EC 3.2.1.23) is the primary defect in the three clinical forms (infantile, juvenile, and adult) of GM1 gangliosidosis and in Morquio B syndrome. Patients with the infantile form of GM1 gangliosidosis (type 1), who usually die before the age of 3 years, display the coarse face, hepatosplenomegaly, and skeletal dysplasia reminiscent of Hurler disease. Cases with later onset, described as the late infantile/juvenile form (type 2), display progressive psychomotor loss but less prominent dysmorphic changes. Extrapyramidal signs of protracted course are the major neurologic manifestations …