Body mass index linked to chromosome 10p but GAD2 does not appear to be involved

Body mass index (BMI) is linked to chromosome 10p in the U.K. population but GAD2 dos not appear to be involved.

According to recent research from England, "Obesity is a major health problem, and many family-based studies have suggested that it has a strong genetic basis. We performed a genome-wide quantitative trait linkage scan for loci influencing BMI [(body mass index)] in 573 pedigrees from the U.K."

C.J. Groves and colleagues working with Churchill Hospital identified "genomewide significant linkage (logarithm of odds=3.74, between D10S208 and D10S196, genomewide p=0.0186) on chromosome 10p. The size of our study population and the statistical significance of our findings provide substantial contributions to the body of evidence for a locus on chromosome 10p."

They continued, "We examined eight single nucleotide polymorphisms (SNPs) in GAD2, which maps to this linkage region, tagging the majority of variation in the gene, and observed marginally significant (0.01<p<0.05) associations between four common variants and BMI. However, these SNPs did not account for our evidence of linkage to BMI, and they did not replicate (in direction of effect) the previous associations."

"We therefore conclude," stated the authors, "that these SNPs are not the etiological variants underlying this locus. We cannot rule out the possibility that other untagged variations in GAD2 may, in part, be involved, but it is most likely that alternative gene(s) within the broad gene-rich region of linkage on 10p are responsible for variation in body mass and susceptibility to obesity."

Groves and colleagues published their study in Diabetes (Significant linkage of BMI to chromosome 10p in the U.K. population, and evaluation of GAD2 as a positional candidate. Diabetes, 2006;55(6):1884-1889).

For additional information, contact C.J. Groves, Churchill Hospital, Oxford Center Diabetes Endocrinol & Metab, Old Rd., Oxford OX3 7LJ, England.

Publisher contact information for the journal Diabetes is: American Diabetes Association, 1701 N Beauregard St., Alexandria, VA 22311-1717, USA.