Linkage study of early-onset obesity to leptin receptor gene in Italian children

Analyses of twins as well as adopted children have shown that obesity has a considerable genetic component. An identical by descent (IBD) study in obese patients with very early onset of the disease has been performed in order to evaluate the linkage of the leptin receptor gene (OB-R) to obesity. Forty-eight couples of discordant (affected-unaffected) Italian sibs have been chosen. Two highly polymorphic microsatellites within introns 1 and 14 of OB-R have been scored. Analysis of the haplotypes did not show any evidence of linkage (p 0.076). Quantitative trait linkage analysis evaluated by regressing the difference of the BMI between the two sibs of a pair as a function of the estimated proportion of alleles shared failed to show any significative evidence for linkage.