title: Nine novel COL4A3 and COL4A4 mutations and polymorphisms identified in inherited membrane diseases.
abstract: Both thin basement membrane nephropathy (TBMN) and autosomal recessive Alport syndrome result from mutations in the COL4A3 and COL4A4 genes, and this study documents further mutations and polymorphisms in these genes. Thirteen unrelated children with TBMN and five individuals with autosomal recessive Alport syndrome were examined for mutations in the 52 exons of COL4A3 and the 47 coding exons of COL4A4 using single-stranded conformation polymorphism (SSCP) analysis. Amplicons producing different electrophoretic patterns were sequenced, and mutations were defined as variants that changed an amino acid but were not present in 50 non-hematuric normals. Three further novel mutations were identified. These were IVS 22-5 T>A in the COL4A3 gene in a consanguineous family with autosomal recessive Alport syndrome, and R1677C and R1682Q in the COL4A4 gene. In addition, six novel polymorphisms (G455G, I462I, G736G and IVS 38-8 G>A in COL4A3, and L658L and A1577A in COL4A4) were demonstrated.Many different COL4A3 and COL4A4 mutations cause TBMN and autosomal recessive Alport syndrome. The identification of polymorphisms in these genes is particularly important to enable diagnostic laboratories to distinguish mutations from uncommon normal variants.
authors.affiliation: Department of Medicine (AH/NH), The Northern Hospital, University of Melbourne, Epping, VIC, 3076, Australia.
authors.forename: Kesha
authors.initials: K
authors.lastname: Rana
authors.forename: Stephen
authors.initials: S
authors.lastname: Tonna
authors.forename: Yan Yan
authors.initials: YY
authors.lastname: Wang
authors.forename: Lydia
authors.initials: L
authors.lastname: Sin
authors.forename: Tina
authors.initials: T
authors.lastname: Lin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Shaw
authors.forename: Ishanee
authors.initials: I
authors.lastname: Mookerjee
authors.forename: Judy
authors.initials: J
authors.lastname: Savige
mesh_terms: D000293:Adolescent; D001324:Autoantigens / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D024141:Collagen Type IV / Q000235:genetics*; D005091:Exons; D005260:Female; D050533:Glomerular Basement Membrane / Q000473:pathology*; D006417:Hematuria / Q000235:genetics; D006801:Humans; D007438:Introns; D007678:Kidney Glomerulus / Q000473:pathology*; D008297:Male; D009154:Mutation; D009394:Nephritis, Hereditary / Q000235:genetics*; D011110:Polymorphism, Genetic; D011507:Proteinuria / Q000235:genetics
chemical_list: D001324:Autoantigens; C466620:COL4A4 protein, human; D024141:Collagen Type IV; C057112:type IV collagen alpha3 chain