Independent confirmation of a major locus for obesity on chromosome 10

Linkage results obtained in genome-wide scans for complex phenotypes require confirmation in independent samples. Recently, linkage of obesity to chromosome 10p12 with a maximal multipoint LOD score of 4.85 was reported upon use of an affected sib-pair approach including nuclear families in which the adult index case had a BMI ≥ 40 kg/m² and at least one further sibling had a BMI ≥ 27 kg/m² (Hager et al., 1998, Nat Genet 20:304-8). To attempt to replicate this linkage finding we genotyped 11 markers spanning approximately 23 cM from 10p13 to 10q11 in a total of 386 individuals stemming from 93 nuclear families with two or more young obese offspring with a BMI ≥ 90th age percentile. The highest multipoint maximum likelihood binomial (MLB) LOD score using the extreme concordant sib-pair approach in which one sib had a BMI ≥ 95th percentile, and other sibs a BMI ≥ 90^th percentile was 2.32. Six markers yielded nominal p-values < 0.05, the highest two point MLB-LOD score of 2.45 (nominal p = 0.0004) was obtained for the marker TCF8. Transmission disequilibrium tests for the most frequent parental allele yielded no nominal p-value < 0.05. The linkage results confirm the presence of a major susceptibility locus for obesity in a region near the centromere on chromosome 10.