RNASEH1 gene variants are associated with autoimmune type 1 diabetes in Colombia

Abstract

Background

In a previous work, we found linkage and association of type 1 diabetes (T1D) to a 12 known gene region at chromosome 2p25 in Colombian families. Here, we present further work on this candidate region.

Materials and methods

Seventeen SNPs located on the 12 candidate genes, in 100 familial trios set, were tested by ARMS–tetraprimer–PCR or PCR–RFLP. Five extra SNPs in the vicinity of rs10186193 were typed. A replica phase included 97 novel familial trios, in whom diabetes-related auto-antibodies (AABs) were tested in sera of the patients. In addition to transmission disequilibrium tests, haplotype analyses were carried out using the unphased software.

Results

SNP rs10186193 (at RNASEH1 gene) showed association with T1D (P = 0.005). The additional five SNPs revealed that rs7607888 (P = 2.03 × 10⁻⁷), rs55981318 (P = 0.018), and rs1136545 (P = 1.93 × 10⁻⁹) were also associated with T1D. Haplotype analysis showed association for rs55981318–rs10186193 (P = 0.0005), rs7563960–rs7607888 (P = 0.0007), rs7607888–rs1136545 (P = 9.21 × 10⁻¹⁰), and rs1136545–rs11538545 (P = 6.67 × 10⁻⁸). In contrast, the new set of 97 familial trios tested for SNPs rs55981318, rs10186193, and rs7607888 did not support the previous finding; however, by combining the sample (197 trios), evidence of association of T1D with rs55981318 and rs7607888 was conclusive. In addition, a two-loci haplotype analysis of the combined sample showed significant association of RNASEH1 with T1D (P = 3.1 × 10⁻⁵).

Conclusion

In conclusion, our analyses suggest that RNASEH1 gene variants associate with susceptibility/protection to T1D in Colombia.

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