Deletion of the late cornified envelope genes, LCE3C and LCE3B, is associated with rheumatoid arthritis.

Methods: We tested for association between the LCE3C_LCE3B copy number variant and a single-nucleotide polymorphism in strong linkage disequilibrium with this variant (rs4112788) and RA in 2 independent case-control data sets (197 and 400 samples from patients with RA, respectively, and 411 and 567 samples from control subjects, respectively), collected at 4 Spanish hospitals. All samples were directly typed for presence of the LCE3C_LCE3B deletion (LCE3C_LCE3B-del) by polymerase chain reaction, and association analysis was performed using the SNPassoc R package.

Results: An association of homozygosity for the LCE3C_LCE3B-del and rs4112788 C allele with the risk of RA was observed in the first data set and was replicated in an independent case-control set. A combined analysis showed an overall P value of 0.0012 (odds ratio [OR] 1.45, 95% confidence interval [95% CI] 1.16-1.81) for association of the LCE3C_LCE3B-del. When the analysis was stratified for serologic data, we observed association in anti-cyclic citrullinated peptide (anti-CCP)-positive patients (P = 0.012, OR 1.51 [95% CI 1.09-2.13]) but not in anti-CCP-negative patients.

Conclusion: An association of homozygosity for the LCE3C_LCE3B-del and rs4112788 C allele with the risk of RA was observed in the first data set and was replicated in an independent case-control set. A combined analysis showed an overall P value of 0.0012 (odds ratio [OR] 1.45, 95% confidence interval [95% CI] 1.16-1.81) for association of the LCE3C_LCE3B-del. When the analysis was stratified for serologic data, we observed association in anti-cyclic citrullinated peptide (anti-CCP)-positive patients (P = 0.012, OR 1.51 [95% CI 1.09-2.13]) but not in anti-CCP-negative patients.