Genome-wide association analysis in sarcoidosis and Crohn's disease unravels a common susceptibility locus on 10p12.2.
OBJECTIVE
Crohn's disease (CD) and sarcoidosis (SA) are chronic inflammatory barrier diseases that share several clinical and immunological features, including the occurrence of granulomas.


METHODS
A 100k genome-wide association study with 83,360 single-nucleotide polymorphisms (SNPs) was performed on 382 CD patients, 398 SA patients, and 394 control individuals. The 24 SNPs that were most strongly associated in the combined CD/SA phenotype were selected for verification in an independent sample of 1,317 patients (660 CD and 657 SA) and 1,091 controls.


RESULTS
The most significant association (Bonferroni corrected P = .036) was obtained at SNP rs1398024 on chromosome 10p12.2, with an odds ratio (OR) for both diseases of 0.81 (95% confidence interval [CI], 0.69-0.96) for carriership of the rarer allele A. The P value in the overall combined sample was 4.24 x 10(-6). During further follow-up, a moderate association (OR, 0.83; 95% CI, 0.72-0.96; P = .015) was observed between rs1398024 and ulcerative colitis (1,080 patients vs 1,091 controls), the second main subphenotype of inflammatory bowel disease in addition to CD. Extensive fine mapping of the 10p12.2 locus points to yet unidentified variants in the C10ORF67 gene region as the most likely underlying risk factors.


CONCLUSIONS
Our study demonstrates that the combined analysis of different, albeit clinically related, phenotypes can lead to the identification of common susceptibility loci.
Franke
Andre
A
Institute for Clinical Molecular Biology, Christian-Albrechts-University, Kiel, Germany.
Fischer
Annegret
A
Nothnagel
Michael
M
Becker
Christian
C
Grabe
Nils
N
Till
Andreas
A
Lu
Tim
T
Müller-Quernheim
Joachim
J
Wittig
Michael
M
Hermann
Alexander
A
Balschun
Tobias
T
Hofmann
Sylvia
S
Niemiec
Regina
R
Schulz
Sabrina
S
Hampe
Jochen
J
Nikolaus
Susanna
S
Nürnberg
Peter
P
Krawczak
Michael
M
Schürmann
Manfred
M
Rosenstiel
Philip
P
Nebel
Almut
A
Schreiber
Stefan
S
D002874:Chromosome Mapping; D002879:Chromosomes, Human, Pair 10; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000235:genetics; D003424:Crohn Disease / Q000453:epidemiology / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D015894:Genome, Human; D023281:Genomics; D005838:Genotype; D006801:Humans; D016017:Odds Ratio; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D012507:Sarcoidosis / Q000453:epidemiology / Q000235:genetics*