The common pentanucleotide polymorphism of the 3'-untranslated region of the leptin receptor gene is associated with obesity in Saudi females *

Obesity is due to the combined effects of genes, environment, lifestyle, and the interactions of these factors. Leptin receptor (LEPR) gene has been intensively evaluated in the search of variants that could be related to obesity. The results of most of these studies have been controversial. We investigated the effects of leptin receptor gene 3’-untranslated region (3’-UTR) polymorphism on phenotype, metabolic parameters and anthropometric measurements of obese Saudi females. 122 healthy women aged 19 to 36 years. The subjects were divided into 3 groups according to their body mass index BMI; lean (BMI 18 - 24), overweight (BMI 25 - 29) and obese (BMI ≥ 30). There were 13 homozygotes and 34 heterozygotes for the 3’-UTR insertion allele amongst all 122 women. The results of this study show that the allele frequency of the insertion allele (I) of 3’UTR was significantly higher in overweight (35.3) and obese females (32.2) compared to the frequency in lean females (15.6). The insertion allele was associated with increased BMI in obese groups. The results obtained from this study indicated that in the obese subjects most variable values increased in I/I homozygote but the significant high value recorded among BMI (40.9 ± 7.11 kg/m2, P = 0.042). Our findings indicated that, the obesity in Saudi females is influenced by alteration in the leptin receptor gene 3’-UTR polymorphism.