title: Methemoglobin reductase deficiency:  novel mutation is associated with a disease phenotype of intermediate severity.
abstract: BACKGROUND
  Cytochrome b5 reductase (CB5R) deficiency is a recessively inherited autosomal disorder that is either benign (type I) or associated with severe neurological problems (type II). Specific mutations in the CYB5R gene are not exclusive to each type.
  
  
  METHODS
  Two cyanotic children with developmental delay but with slow progression were investigated for CB5R deficiency. A novel mutation, p.Arg58Pro, was independently detected in both cases.
  
  
  CONCLUSIONS
  The clinical variability and severity of the disease reflect the combined effects of impaired function of the 2 mutant enzymes. As illustrated by these 2 cases, inheritance of p.Arg58Pro with either p.Gly76Ser or pLeu188del causes a clinical condition more severe than type I and less severe than the type II cases reported to date.
authors.affiliation: Department of Haematology, Belfast City Hospital, Belfast, Northern Ireland. melanie.percy@belfasttrust.hscni.net
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Percy
authors.forename: Chris
authors.initials: C
authors.lastname: Barnes
authors.forename: Gemma
authors.initials: G
authors.lastname: Crighton
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Leventer
authors.forename: Robert
authors.initials: R
authors.lastname: Wynn
authors.forename: Terence R
authors.initials: TR
authors.lastname: Lappin
mesh_terms: D002675:Child, Preschool; D042966:Cytochrome-B(5) Reductase / Q000172:deficiency* / Q000235:genetics*; D002658:Developmental Disabilities / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008708:Methemoglobinemia / Q000150:complications / Q000201:enzymology* / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D011379:Prognosis
chemical_list: D042966:Cytochrome-B(5) Reductase