title: Mutational analysis of the HGSNAT gene in Italian patients with mucopolysaccharidosis IIIC (Sanfilippo C syndrome). Mutation in brief #959. Online.
abstract: Mucopolysaccharidosis (MPS) describes any inherited lysosomal storage disorder resulting from an inability to catabolize glycosaminoglycans. MPS III (or Sanfilippo syndrome) is an autosomal recessive disease caused by a failure to degrade heparan sulphate. There are four subtypes of MPS III, each categorized by a deficiency in a specific enzyme involved in the heparan sulphate degradation pathway. The genes mutated in three of these (MPS IIIA, MPS IIIB, and MPS IIID) have been cloned for some time. However, only very recently has the gene for MPS IIIC (heparin acetyl CoA: alpha-glucosaminide N-acetyltransferase, or HGSNAT) been identified. Its product (previously termed transmembrane protein 76, or TMEM76) has little sequence similarity to other proteins of known function, although it is well conserved among all species. In this study, a group of MPS IIIC patients, who are mainly of Italian origin, have been clinically characterized. Furthermore, mutational analysis of the HGSNAT gene in these patients resulted in the identification of nine alleles, of which eight are novel. Three splice-site mutations, three frameshift deletions resulting in premature stop codons, one nonsense mutation, and two missense mutations were identified. The latter are of particular interest as they are located in regions which are predicted to be of functional significance. This research will aid in determining the molecular basis of HGSNAT protein function, and the mechanisms underlying MPS IIIC.
authors.affiliation: Telethon Institute of Genetics and Medicine, Naples, Italy.
authors.forename: Anthony Olind
authors.initials: AO
authors.lastname: Fedele
authors.forename: Mirella
authors.initials: M
authors.lastname: Filocamo
authors.forename: Maja
authors.initials: M
authors.lastname: Di Rocco
authors.forename: Giovanna
authors.initials: G
authors.lastname: Sersale
authors.forename: Torben
authors.initials: T
authors.lastname: Lübke
authors.forename: Paola
authors.initials: P
authors.lastname: di Natale
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Cosma
authors.forename: Andrea
authors.initials: A
authors.lastname: Ballabio
mesh_terms: D000123:Acetyltransferases / Q000235:genetics*; D000483:Alleles; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007558:Italy; D008297:Male; D009084:Mucopolysaccharidosis III / Q000235:genetics* / Q000503:physiopathology; D009154:Mutation
chemical_list: D000123:Acetyltransferases; C514442:HGSNAT protein, human