Association of the ATP-binding cassette transporter A1 R230C variant with early-onset type 2 diabetes in a Mexican population

OBJECTIVE - The ATP-binding cassette transporter A1 (ABCA1) R230C variant is associated with low HDL cholesterol levels, obesity, and the metabolic syndrome in Mexican-Mestizos. Because a pivotal role for ABCA1 in pancreatic β-cell function was recently observed in the mouse model, we assessed the association of this variant with type 2 diabetes in this population. RESEARCH DESIGN AND METHODS - The initial group included 446 unrelated Mexican individuals: 244 with type 2 diabetes aged 20-69 years (121 with onset ≤45 years), and 202 nondiabetic control subjects aged >50 years. An independent study group included 242 type 2 diabetic case subjects and 225 control subjects with similar characteristics. RESULTS - R230C/C230C genotypes were significantly more frequent in type 2 diabetic individuals (24.6%) than in control subjects (11.4%) in the initial study group (OR 2.501; P = 0.001). After stratifying by age at diagnosis, the association was significant only in the early-onset group (age at diagnosis ≤45 years) (OR 3.776, P = 3.3 × 10^-6). Both associations remained significant after adjusting for admixture (P = 0.0008 and P = 8.1 × 10^-6, respectively). Similar trends were observed in the independent study group, and the combined analysis of both populations showed a highly significant association of the R230C variant with type 2 diabetes, particularly with that of early onset (P = 7.6 × 10^-6 and 9.4 × 10^-8, respectively). CONCLUSIONS - The R230C ABCA1 variant is associated with type 2 diabetes, particularly of early onset, in the Mexican-Mestizo population.