Association of genetic variants in the adiponectin encoding gene (ADIPOQ) with type 2 diabetes in Japanese Brazilians

Aim The objective of this study is to assess the contribution of ADIPOQ variants to type 2 diabetes in Japanese Brazilians. Methods We genotyped 200 patients with diabetes mellitus (100 male and 100 female, aged 55.0 years [47.5–64.0 years]) and 200 control subjects with normal glucose tolerant (NGT) (72 male and 128 female, aged 52.0 years [43.5–64.5 years]). Results Whereas each polymorphism studied (T45G, G276T, and A349G) was not significantly associated with type 2 diabetes mellitus, the haplotype GGA was overrepresented in our diabetic population (9.3% against 3.1% in NGT individuals, P =.0003). Also, this haplotype was associated with decreased levels of adiponectin. We also identified three mutations in exon 3: I164T, R221S, and H241P, but, owing to the low frequencies of them, associations with type 2 diabetes could not be evaluated. The subjects carrying the R221S mutation had plasma adiponectin levels lower than those without the mutation (2.10 μg/ml [1.35–2.55 μg/ml] vs. 6.68 μg/ml [3.90–11.23 μg/ml], P =.015). Similarly, the I164T mutation carriers had mean plasma adiponectin levels lower than those noncarriers (3.73 μg/ml [3.10–4.35 μg/ml] vs. 6.68 μg/ml [3.90–11.23 μg/ml]), but this difference was not significant ( P =.17). Conclusions We identified in the ADIPOQ gene a risk haplotype for type 2 diabetes in the Japanese Brazilian population.