The leptin receptor has potential role in the development of obesity. Recently, some evidence has been found for the polymorphisms in the leptin receptor gene also being involved in human obesity. We have examined associations between the Gln223Arg polymorphism in the leptin receptor gene and fat distribution in Koreans.
Eighty-three in obese subjects (BMI; ≥30 kg/m2) and eighty-one in normal weight subjects (BMI; 18.5～24.9 kg/m2) were studied after informed consent. BMI, waist circumference, hip circumference, WHR, subcutaneous fat, and visceral fat amount by abdominal CT at the level of umbilicus were measured in the both groups. Leptin receptor polymorphism was detected by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assays.
Twenty-seven (32.5%) subjects were heterozygous and fifty-six (67.5%) subjects were homozygous (Arg223) for the leptin receptor gene in the obese group. The frequency of the Arg223 allele was 0.83. Forty-one (50.6%) subjects were heterozygous and forty (49.4%) subjects were homozygous (Arg223) for the leptin receptor gene in the normal weight group. The frequency of the Arg223 allele was 0.75. There was significant difference in the allele frequency between both group (p=0.026). After adjustment for age, sex and BMI, significant difference was found in visceral fat amount between mutant homozygous and heterozygous of Gln223Arg in the leptin receptor gene from the normal weight subjects (p<0.05).
Gln223Arg polymorphism of the Leptin receptor gene appeared to be a genetic risk factor for obesity. This study suggests that the Gln223Ala polymorphism of the Leptin receptor gene has a causative role to body fat distribution in Korean.

Keywords: Leptin receptor gene, Gln223Arg, Fat distribution