Association of copy number variation in the AHI1 gene with risk of obesity in the Chinese population.

OBJECTIVE

The prevalence of obesity has increased dramatically over the past decade. Gene copy number variants (CNVs) have been recognized as a hereditable source of susceptibility in human complex diseases including obesity. Recent studies have shown that Abelson helper integration site 1 (Ahi1) gene has a significant contribution in the homeostasis regulation in mouse models of obesity. A study was therefore carried out to investigate whether CNVs in AHI1 gene contribute to human obesity.

SUBJECTS AND METHODS

We analyzed samples from 70 Chinese overweight adults and 74 healthy controls for DNA copy number change using the Affymetrix single-nucleotide polymorphism (SNP) 6.0 array. Validation of CNVs of AHI1 was achieved by real-time PCR using the ΔΔC(t) method.

RESULTS

Copy number gain analysis revealed significant gains (P=0.0017) of AHI1 gene copy number in 17 of 70 (24.3%) samples but only four of 74 (5.4%) controls overall. Then we studied the frequency distribution of CNVs in AHI1 gene according to body mass index (BMI) grade. Five out of 28 (18.5%) at-risk obese, six out of 26 (26.9%) moderate obese, and six out of 17 (29.4%) severe obese subjects studied showed increased AHI1 gene copy number.

CONCLUSIONS

The result suggested that there was a significant linear trend for increasing AHI1 gene copy number frequencies with increasing BMI.