title: Metachromatic leukodystrophy without arylsulfatase A deficiency: a new case of saposin-B deficiency.
abstract: Metachromatic leukodystrophy (MLD) is an autosomal recessive neurodegenerative lysosomal disease characterized by accumulation of sulfatides, extensive white matter damage and loss of both cognitive and motor functions. In vivo, the catabolism of sulfatide requires both the enzyme arylsulfatase A and a specific sphingolipid activator protein, saposin-B, encoded by the PSAP gene. Arylsulfatase A activity is deficient in the classical forms of MLD, but exceedingly rare cases of MLD are due to saposin-B deficiency. We report here a detailed clinical, radiological and histological description of a new case in a 2-year-old Italian girl, who presented as a late infantile case of MLD with normal arylsulfatase A activity, urinary excretion of sulfatides and mutations in the PSAP gene.
authors.affiliation: Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Av. J.J. Crocq 15, 1020 Brussels, Belgium. nicolas.deconinck@huderf.be
authors.forename: Nicolas
authors.initials: N
authors.lastname: Deconinck
authors.forename: Anissa
authors.initials: A
authors.lastname: Messaaoui
authors.forename: France
authors.initials: F
authors.lastname: Ziereisen
authors.forename: Hazim
authors.initials: H
authors.lastname: Kadhim
authors.forename: Yves
authors.initials: Y
authors.lastname: Sznajer
authors.forename: Karine
authors.initials: K
authors.lastname: Pelc
authors.forename: Marie Cécile
authors.initials: MC
authors.lastname: Nassogne
authors.forename: Marie T
authors.initials: MT
authors.lastname: Vanier
authors.forename: Bernard
authors.initials: B
authors.lastname: Dan
mesh_terms: D002553:Cerebroside-Sulfatase / Q000378:metabolism*; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007966:Leukodystrophy, Metachromatic / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D046529:Microscopy, Electron, Transmission; D010525:Peripheral Nerves / Q000473:pathology / Q000648:ultrastructure; D049231:Saposins / Q000172:deficiency*
chemical_list: D049231:Saposins; D002553:Cerebroside-Sulfatase