A polymorphic marker in the leptin gene associated with Japanese morbid obesity

Abstract

The prevaleance of morbid obesity (body mass index of 35.0 or greater) is low in Japan (0.2-0.3%), and little systematic investigation of its cause in this population has been carried out. Leptin plays a central role in regulation of body weight; mice deficient in leptin develop marked obesity. We sought mutations in the leptin gene in 53 morbidly obese Japanese (maximum body mass index 35-60) including 46 with type 2 diabetes. Direct DNA sequencing was performed following polymerase chain reaction amplification. Apart from a silent mutation at codon 25 (CAA/CAG, glutamine) detected in eight subjects, no mutations were detected. We found a significantly higher prevalence of the variant leptin 25CAG allele among the 53 obese subjects (0.085) studied than in 132 nonobese control subjects (0.011, P<0.001). In Japanese populations mutations in the protein coding sequence of the leptin gene are unlikely to be a major cause of morbid obesity. However, the leptin 25CAG allele may be linked to morbid obesity in this population. Specifically, genetic variation located near the leptin gene may be involved in pathogenesis. The leptin polymorphism 25CAG appears to be a new genetic marker for obesity susceptibility, at least in Japanese.

Analysis of 825C/T Polymorphism of G Proteinβ3 Subunit in Obese/Diabetic Japanese

“…The most obese 55 subjects, all of whom had BMI of at least 35 kg/m 2 , were divided into a subgroup. A BMI of 35 kg/m 2 represents the 99.7 to 99.8th percentile in the Japanese population and is commonly used as a criterion for extreme obesity in Japan (12). Genotypic and allelic frequencies in 150 controls, 208 obese subjects, and in the subgroup of 55 extremely obese subjects were similar and not significantly different.…”

“…A BMI of 30 kg/m 2 represents the 97-98th percentile in the Japanese population, a level equivalent a BMI of 40 kg/m 2 in Americans (reviewed in ref. 12). There were 118 males and 90 females, 146 of whom had type 2 diabetes.…”

Prevalence of nonalcoholic steatohepatitis in Japanese patients with morbid obesity undergoing bariatric surgery

“…Although the prevalence of morbid obesity is low in Japan (0.25-0.3 %) in comparison with the USA [26,27], it is increasing. We previously investigated the clinical characteristics of severely obese Japanese patients undergoing laparoscopic Roux-en-Y gastric bypass surgery [28].…”

Nonalcoholic fatty liver disease in Japanese patients with severe obesity who received laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in comparison to non-Japanese patients

“…2,3 Although the prevalence of NAFLD in the general population is estimated to range from 3% to 24%, depending on the defi nition, 4,5 85%-95% of morbidly obese persons in the United States seem to have NAFLD and up to 33% have nonalcoholic steatohepatitis (NASH). [6][7][8][9] Although the prevalence of morbid obesity is low in Japan (0.25%-0.3%) in comparison with the United States, 10,11 it is nevertheless increasing these days.…”