The strongest association was detected with rs12903120 (p=5.45×10−8, inflation corrected p=1.09×10−6) in an uncharacterized gene, C15orf53 on chromosome 15q14. Two other genotyped SNPs, rs12916379 and rs2132157, that are highly correlated with rs12903120 (D′=1, r2=1 in HapMap EUR reference sample) also showed strong association with SC (with inflation corrected p=2.79×10−6 and p=3.02×10−6, respectively) (Table S3). Rs12916379 is located in the 3′ un-translated region of C15orf53 (Figure 3). Using imputed genotypes, 15 additional SNPs in C15orf53 gene region also showed suggestive evidence of association (inflation corrected p≤1.0×10−5) with SC (Table S3). Three of these 15 SNPs have stronger association (inflation corrected 9.4×10−7≤ p ≤9.7×10−7) with SC than the genotyped SNP rs12903120. A non-synonymous coding SNP in C15orf53 that is highly correlated with rs12903120 (rs7165988; r2=0.95, D′=1 in HapMap EUR reference sample) is associated with SC at an inflation corrected p=1.7×10−6.
