Identification of two novel missense mutations in the human OB gene

OBJECTIVE: To clone the human OB gene and to investigate if mutations in the OB gene are related to juvenile onset obesity in Caucasians.

DESIGN: Case-cohort study with mutational scanning of the OB gene in an obese cohort and in a population sample of young Caucasians.

SUBJECTS: An obese cohort of 156 subjects with juvenile onset obesity and a population sample of 380 healthy young Caucasians.

MEASUREMENTS: Various anthropometric and biochemical measures of obesity and insulin sensitivity and single strand conformation polymorphism scanning and nucleotide sequencing.

RESULTS: Analysis of the coding region of the OB gene in the 536 participants revealed that one obese subject was heterozygous for a mutation at codon Phe17Leu and one normal weight subject was heterozygous for a mutation at codon Val110Met. The phenotypes of the carriers were not different from matched non-mutation carrying subjects.

CONCLUSIONS: Mutations exist in the OB gene among obese as well as lean subjects although they are rare. However, it is unlikely that mutations in the coding region of the OB gene are a common cause of juvenile onset obesity among Caucasians.