Mutations in the human Jagged1 gene are responsible for Alagille syndrome.
Alagille syndrome (AGS) is an autosomal-dominant disorder characterized by intrahepatic cholestasis and abnormalities of heart, eye and vertebrae, as well as a characteristic facial appearance. Identification of rare AGS patients with cytogenetic deletions has allowed mapping of the gene of 20p12. We have generated a cloned contig of the critical region and used fluorescent in situ hybridization on cells from patients with submicroscopic deletions to narrow the candidate region to only 250 kb. Within this region we identified JAG1, the human homologue of rat Jagged1, which encodes a ligand for the Notch receptor. Cell-cell Jagged/Notch interactions are known to be critical for determination of cell fates in early development, making this an attractive candidate gene for a developmental disorder in humans. Determining the complete exon-intron structure of JAG1 allowed detailed mutational analysis of DNA samples from non-deletion AGS patients, revealing three frame-shift mutations, two splice donor mutations and one mutation abolishing RNA expression from the altered allele. We conclude that AGS is caused by haploinsufficiency of JAG1.
Oda
T
T
Laboratory of Gene Transfer, National Human Genome Research Institutes of Health, Bethesda, Maryland 20892-4442, USA.
Elkahloun
A G
AG
Pike
B L
BL
Okajima
K
K
Krantz
I D
ID
Genin
A
A
Piccoli
D A
DA
Meltzer
P S
PS
Spinner
N B
NB
Collins
F S
FS
Chandrasekharappa
S C
SC
D016738:Alagille Syndrome / Q000235:genetics*; D002135:Calcium-Binding Proteins; D002460:Cell Line; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D017931:DNA Primers; D005091:Exons / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D036341:Intercellular Signaling Peptides and Proteins; D007438:Introns / Q000235:genetics; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D018807:Polymorphism, Single-Stranded Conformational; D012326:RNA Splicing / Q000235:genetics; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion / Q000235:genetics; D000072099:Serrate-Jagged Proteins; D014157:Transcription Factors
D002135:Calcium-Binding Proteins; D017931:DNA Primers; D036341:Intercellular Signaling Peptides and Proteins; C000606273:JAG1 protein, human; C000606275:Jag1 protein, rat; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D000072099:Serrate-Jagged Proteins; D014157:Transcription Factors