Although polymorphism of the
mitochondrial DNA 15497guanine/
adenine (Mt15497G-->A) leads to the Gly251Ser
amino acid replacement on human
cytochrome b, it is unknown whether functional alteration of the mitochondrion is induced by the Gly251Ser replacement. To see if an association exists between the Mt15497G-->A polymorphism and
obesity, we examined differences in body size, body composition, and regional body fat distribution between the two genotypes in middle-aged and elderly Japanese individuals (825 women and 906 men). The Mt15497 genotype was determined with an automated colorimetric allele-specific
DNA probe assay system using the polymerase chain reaction (PCR) method. The Mt15497G-->A polymorphism was detected in 3.5% ( n=60) of all subjects: 2.8% ( n=23) among women and 4.1% ( n=37) among men. After adjusting for age and smoking, we found that
body weight, body mass index, waist and hip circumferences, fat mass, fat-free mass, intra-abdominal fat and
triglycerides were significantly greater in women with the A allele compared with the G allele ( p=0.001-0.025). For men, waist to hip ratio was significantly greater ( p=0.032), and waist circumference, intra-abdominal fat and
triglycerides had a trend to be significantly greater ( p=0.062-0.087) in subjects with the A allele compared with the G allele. These data suggest that the Mt15497 polymorphism may be associated with
obesity-related variables and lipid metabolism.