Adult-onset MLD: A gene mutation with isolated polyneuropathy

A 22-year-old man presented with recurrent ulnar mononeuropathies and diffu sely slow nerve conduction velocities. Arylsulfatase A (ASA) activity from leukocytes and fibroblasts was reduced, and urinary sulfatides were increas ed. Sural nerve biopsy revealed a reduction in myelinated fibers and Schwan n cell inclusions. Results of studies of CNS integrity, including cranial M RI, evoked potentials, and neuropsychologic tests, were normal. Molecular g enetic analyses revealed a novel homozygous missense mutation (Thr286Pro) i n the ASA gene.