title: A novel mutation in the AMELX gene and multiple crown resorptions.
abstract: Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders with regard to genetic aetiology and clinical phenotype and affects tooth enamel with no other non-oral syndromic conditions. X-linked AI is caused by mutations in the amelogenin (AMELX) gene, the only AI candidate gene located on the X chromosome. To date, 15 mutations in the AMELX gene have been found to cause AI. We identified a proband with generalized hypoplastic enamel and unusual multiple crown resorption in premolars and molars. Pedigree analysis suggested an X-linked hereditary pattern. We performed mutational analysis for the AMELX gene based on the candidate gene approach. Sequencing analysis revealed a novel mutation in exon 6 (g.4090delC, c.517delC, p.Pro173LeufsX16). This frameshift mutation produces a premature stop codon within exon 6 and is predicted to replace 33 amino acids at the C-terminus with 15 novel amino acids if the mutant mRNA escapes the nonsense-mediated decay system. Although crown resorptions occur frequently in patients with the hypoplastic type of A1, an association with the AMELX mutation has not been previously reported. We believe that these findings will broaden our understanding of the clinical phenotype and pathogenesis of X-linked AI.
authors.affiliation: Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Chongno-gu, Seoul, Korea.
authors.forename: Kyung-Eun
authors.initials: KE
authors.lastname: Lee
authors.forename: Sook-Kyung
authors.initials: SK
authors.lastname: Lee
authors.forename: Seung-Eun
authors.initials: SE
authors.lastname: Jung
authors.forename: Su Jeong
authors.initials: SJ
authors.lastname: Song
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Cho
authors.forename: Zang Hee
authors.initials: ZH
authors.lastname: Lee
authors.forename: Jung-Wook
authors.initials: JW
authors.lastname: Kim
mesh_terms: D000567:Amelogenesis Imperfecta / Q000150:complications / Q000235:genetics*; D053523:Amelogenin / Q000235:genetics*; D002648:Child; D018389:Codon, Nonsense; D004252:DNA Mutational Analysis; D016368:Frameshift Mutation; D006801:Humans; D008297:Male; D024343:Open Bite / Q000150:complications; D019228:Tooth Crown / Q000473:pathology; D014091:Tooth Resorption / Q000235:genetics*
chemical_list: D053523:Amelogenin; D018389:Codon, Nonsense