DLG5 variants do not influence susceptibility to inflammatory bowel disease in the Scottish population.
BACKGROUND
Recent data have suggested that specific haplotypic variants of the DLG5 gene on chromosome 10q23 may be associated with susceptibility to inflammatory bowel disease (IBD) in Germany. Haplotype D, notably characterised by the presence of a G-->A substitution at nucleotide 113, was associated with susceptibility to Crohn's disease (CD) whereas an extended haplotype A conferred protection.


OBJECTIVE
Association of DLG5 haplotypic variants with disease susceptibility, genotype-phenotype relationships, and epistasis with CARD15 was investigated in the Scottish population.


METHODS
A total of 374 CD, 305 ulcerative colitis (UC), and 294 healthy controls (HC) were studied. Genotyping for the variants rs1248696 (113A, representing haplotype D) and the single nucleotide polymorphism tag rs2289311 (representing haplotype A) were typed using the Taqman system.


RESULTS
On analysis of the DLG5 variant 113A, there were no associations with IBD when allelic frequency (11.4% IBD v 13.2% HC; p = 0.30) and carrier frequency (19.2% IBD v 24.6% HC; p = 0.069) were analysed. No associations were observed between 113A variant allelic frequency (p = 0.37), carrier frequency (p = 0.057), and CD. In fact, 113A heterozygosity rates were lower in CD (16%) and IBD (16.9%) than in HC (23%) (p = 0.029 and p = 0.033, respectively). No associations between DLG5 and UC were observed. Haplotype A was not protective and there was no evidence of epistasis between DLG5 and CARD15.


CONCLUSIONS
The present data contrast strongly with previous data from Germany. DLG5 113A is not associated with disease susceptibility and haplotype A does not confer resistance. Further work is required to evaluate the significance of DLG5 in other populations from geographically diverse regions.
Noble
C L
CL
Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
Nimmo
E R
ER
Drummond
H
H
Smith
L
L
Arnott
I D R
ID
Satsangi
J
J
D000328:Adult; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000235:genetics; D003424:Crohn Disease / Q000453:epidemiology / Q000235:genetics; D004843:Epistasis, Genetic; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology / Q000235:genetics*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D053473:Nod2 Signaling Adaptor Protein; D010641:Phenotype; D012606:Scotland / Q000453:epidemiology; D025521:Tumor Suppressor Proteins / Q000235:genetics*
C114461:DLG5 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; D025521:Tumor Suppressor Proteins