Objective: A substantial proportion of human obesity may be explained by genetic variability. Researchers have tried to identify the important genes in obesity with little sucsess. PPARg2 (peroxisome proliferator activated receptor g 2) is a transcription factor of the nuclear hormone receptor superfamily. It plays a key role in the developement and differentiation of adipocytes. Recently the mutation Pro115Gln in the PPARg2 gene was identified and shown to have a significant correlation with severe obesity. The actual prevalence and distribution of this mutation is not known. The aim of this study was to look for this mutation among Icelandic children suffering from severe obesity.
Material and methods: Thirty-five children and adolescents, aged 4-18, who have been diagnosed with severe obesity participated in the study. Eight parents and siblings aged 19-41 also participated. All study subjects had been obese since early childhood. Body mass index (BMI) was used to describe the phenotype of the subjects. The participants had a BMI of 28.0 to 52.2 kg/m(2). Genomic DNA was extracted from leucocytes. A 131 bp segment was amplified using polymerase chain reaction. The amplified product was digested with the restriction enzyme Hinc II, resolved on agarose gel and visualized under ultraviolet illumination after staining with ethidium bromide. To examine other mutations on the same 131 bp segment enzymatic mutation detection (EMD) was used. Finally the segments giving variable results using EMD were sequenced using the classic Sanger s method.
Results: The mutation Pro115Gln was not found in any of the specimens after analysis of the restriction fragment length polymorphism. The results of EMD indicated mutations or polymorphisms in three of the subjects but DNA sequencing failed to confirm these results.
Conclusions: The mutation Pro115Gln or other genetic alternations within the exon examined do not appear to have a significant role in severe early - onset obesity in Icelandic children.