PCSK1 rs6232 is associated with childhood and adult class III obesity in the Mexican population.

Background: Common variants rs6232 and rs6235 in the PCSK1 gene have been associated with obesity in European populations. We aimed to evaluate the contribution of these variants to obesity and related traits in Mexican children and adults.

Methodology/principal Findings: Rs6232 and rs6235 were genotyped in 2382 individuals, 1206 children and 1176 adults. Minor allele frequencies were 0.78% for rs6232 and 19.99% for rs6235. Rs6232 was significantly associated with childhood obesity and adult class III obesity (OR = 3.01 95%CI 1.64-5.53; P = 4 × 10⁻⁴ in the combined analysis). In addition, this SNP was significantly associated with lower fasting glucose levels (P = 0.01) and with increased insulin levels and HOMA-B (P = 0.05 and 0.01, respectively) only in non-obese children. In contrast, rs6235 showed no significant association with obesity or with glucose homeostasis parameters in any group.

Conclusion/significance: Although rs6232 is rare in the Mexican population, it should be considered as an important risk factor for extreme forms of obesity.