Association of the SNP-19 genotype 22 in the calpain-10 gene with elevated body mass index and hemoglobin A 1c levels in Japanese

Abstract

Background: An association of variations in the calpain-10 gene ( CAPN10) with type 2 diabetes was originally reported in Mexican Americans. However, some studies in other racial groups were contradictory. Methods: We studied the influence of genotypes and haplotype combinations (haplogenotypes) of CAPN10 on the metabolic traits in 286 Japanese subjects who visited a General Health Check-up Center. Results: As for single nucleotide polymorphism (SNP)-19, subjects with genotype 22 had higher body mass index (BMI) and hemoglobin A 1c (HbA 1c) levels than those with genotypes 11 and 12 ( p=0.003 and p=0.024, respectively). In SNP-63, subjects with genotype 11 had higher BMI and HbA 1c levels than those with genotypes 12 and 22 ( p=0.003 and p=0.045, respectively). Subjects who had genotype 22 at SNP-19 always had genotype 11 at SNP-63. Subjects with haplogenotype 121/121 had higher BMI levels ( p=0.021) and tended to have higher HbA 1c levels ( p=0.08) than those with other haplogenotypes. All things considered, SNP-19 genotype 22, which was composed of haplogenotype 121/121 and 121/221, had highest significance level of association with elevated HbA 1c levels. SNP-43 did not affect metabolic traits in our subjects. Subjects with haplogenotype 112/121 rather showed lower BMI and HbA 1c levels ( p=0.016 and p=0.008) than those with all other haplogenotypes. Conclusions: These results indicate the contribution of SNP-19 in CAPN10 to mild obesity and glucose intolerance in Japanese.