title: Pelizaeus-Merzbacher disease, Pelizaeus-Merzbacher-like disease 1, and related hypomyelinating disorders.
abstract: The purpose of this article is to present contemporary information on the clinical and molecular diagnosis and the treatment of Pelizaeus-Merzbacher's disease (PMD) and related leukodystrophies. Various types of mutations of the X-linked proteolipid protein 1 gene (PLP1) that include copy number changes, point mutations, and insertions or deletions of a few bases lead to a clinical spectrum from the most severe connatal PMD, to the least severe spastic paraplegia 2 (SPG2). Signs of PMD include nystagmus, hypotonia, tremors, titubation, ataxia, spasticity, athetotic movements and cognitive impairment; the major findings in SPG2 are leg weakness and spasticity. A diffuse pattern of hypomyelination is seen on magnetic resonance imaging (MRI) of PMD/SPG2 patients. A similar constellation of signs and pattern of hypomyelination lead to the autosomal recessive disease called Pelizaeus-Merzbacher-like disease 1 (PMLD1) and the less-severe spastic paraplegia 44 (SPG44), caused by mutations of the gap junction protein, gamma-2 gene (GJC2), formerly known as the gap junction protein, α-12 gene (GJA12). Magnetic resonance spectroscopy (MRS) and brainstem auditory evoked potentials (BAEP) may assist with differential clinical diagnosis of PMD and PMLD1. Supportive therapy for patients with PMD/SPG2 and PMLD1/SPG44 includes medications for seizures and spasticity; physical therapy, exercise, and orthotics for spasticity management; surgery for contractures and scoliosis; gastrostomy for severe dysphagia; proper wheelchair seating, physical therapy, and orthotics to prevent or ameliorate the effects of scoliosis; special education; and assistive communication devices.
authors.affiliation: Alfred I. duPont Hospital for Children, Nemours Biomedical Research, RC1-235, 1701 Rockland Road, Wilmington, DE 19803, USA. ghobson@nemours.org
authors.forename: Grace M
authors.initials: GM
authors.lastname: Hobson
authors.forename: James Y
authors.initials: JY
authors.lastname: Garbern
mesh_terms: D003711:Demyelinating Diseases / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009154:Mutation / Q000235:genetics; D010264:Paraplegia / Q000175:diagnosis / Q000235:genetics*; D020371:Pelizaeus-Merzbacher Disease / Q000175:diagnosis* / Q000235:genetics* / Q000628:therapy