Mucopolysaccharidosis type IIIA (MPSIIIA), a rare lysosomal storage disorder attributable to mutations in the sulfamidase (SGSH) gene, presents with lysosomal heparan sulfate (HS) accumulation, resulting predominantly in neurodegeneration and peripheral impairments typically identifiable at age 3–4 years, culminating in adolescence fatality.68 The gene discussed is SGSH; the disease is mucopolysaccharidosis type 3A.