After six years of research and genome comparisons, a Taiwanese research team has found that three genetic loci, or positions on a chromosome, are associated with severe obesity in ethnic Chinese.
A summary of the study was published in this month’s issue of the American Journal of Clinical Nutrition.
Severe obesity is associated with novel single nucleotide polymorphisms of the ESR1 and PPAR loci in Han Chinese.
According to Pan Wen-harn (潘文涵), a researcher with the Institute of Biomedical Sciences at Academia Sinica, severe obesity is associated with novel single nucleotide polymorphisms, or DNA sequence variations, of the ESR1 and PPAR loci in ethnic Chinese.
Pan said that many loci associated with obesity have been reported, with at least 18 genes having been replicated in five studies on obesity-related indicators and that 14 additional genes have been associated with obesity in Asians.
Pan and his associates examined these variants identified in medical periodicals in an attempt to find out how many are associated with severe obesity in Han Chinese and how they combine to exert their effects.
In collaboration with Lee Wei-jie (李威傑), vice president of Min-Sheng General Hospital in Taoyuan County, Pan and his group selected 304 severely obese patients with a body mass index (BMI) exceeding 39 from the hospital and 304 control subjects with a BMI of less than 24 selected from Academia Sinica’s Han Chinese Gene Data Bank to participate in a two-stage association study.
Subsequently, 220 additional severely obese patients (BMI 35) and 338 controls (BMI 24) were recruited to replicate the results, Pan said. All of the controls were age, sex, education and residence-matched.
Finally, a pooled analysis was carried out based on all 514 cases and 606 controls with complete information, he added.
In the first stage, in tests on 94 cases and 94 controls, the researchers found 18 potentially associated single nucleotide polymorphisms, Pan said.
The significance of three novel common single nucleotide polymorphisms, one on ESR1 and two on PPAR, were confirmed in the second stage and replicated further, he said.
A combination of the three genes was stronger than that of any individual gene and resulted in a five-times greater risk of severe obesity than in those without the genetic variations.
“This information may contribute to the assessment of the risk of severe obesity,” he said.
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