title: Alagille syndrome in a Vietnamese cohort: mutation analysis and assessment of facial features.
abstract: Alagille syndrome (ALGS, OMIM #118450) is an autosomal dominant disorder that affects multiple organ systems including the liver, heart, eyes, vertebrae, and face. ALGS is caused by mutations in one of two genes in the Notch Signaling Pathway, Jagged1 (JAG1) or NOTCH2. In this study, analysis of 21 Vietnamese ALGS individuals led to the identification of 19 different mutations (18 JAG1 and 1 NOTCH2), 17 of which are novel, including the third reported NOTCH2 mutation in Alagille Syndrome. The spectrum of JAG1 mutations in the Vietnamese patients is similar to that previously reported, including nine frameshift, three missense, two splice site, one nonsense, two whole gene, and one partial gene deletion. The missense mutations are all likely to be disease causing, as two are loss of cysteines (C22R and C78G) and the third creates a cryptic splice site in exon 9 (G386R). No correlation between genotype and phenotype was observed. Assessment of clinical phenotype revealed that skeletal manifestations occur with a higher frequency than in previously reported Alagille cohorts. Facial features were difficult to assess and a Vietnamese pediatric gastroenterologist was only able to identify the facial phenotype in 61% of the cohort. To assess the agreement among North American dysmorphologists at detecting the presence of ALGS facial features in the Vietnamese patients, 37 clinical dysmorphologists evaluated a photographic panel of 20 Vietnamese children with and without ALGS. The dysmorphologists were unable to identify the individuals with ALGS in the majority of cases, suggesting that evaluation of facial features should not be used in the diagnosis of ALGS in this population. This is the first report of mutations and phenotypic spectrum of ALGS in a Vietnamese population.
authors.affiliation: Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Henry C
authors.initials: HC
authors.lastname: Lin
authors.forename: Phuc
authors.initials: P
authors.lastname: Le Hoang
authors.forename: Anne
authors.initials: A
authors.lastname: Hutchinson
authors.forename: Grace
authors.initials: G
authors.lastname: Chao
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gerfen
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Loomes
authors.forename: Ian
authors.initials: I
authors.lastname: Krantz
authors.forename: Binita M
authors.initials: BM
authors.lastname: Kamath
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Spinner
mesh_terms: D016738:Alagille Syndrome / Q000235:genetics*; D044466:Asian People / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000235:genetics; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D005145:Face / Q000002:abnormalities*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D051883:Receptor, Notch2 / Q000235:genetics; D000072099:Serrate-Jagged Proteins; D014744:Vietnam
chemical_list: D002135:Calcium-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; C497764:NOTCH2 protein, human; D051883:Receptor, Notch2; D000072099:Serrate-Jagged Proteins