Analysis of beta3 adrenergic receptor gene polymorphism using noninvasive samples obtained at scheduled infant health checkups.

Obesity is a risk factor for life-style-related diseases, and is based on three factors: genetic, environmental, and life-style. In adults, it is difficult to achieve and maintain normal body weight, so it is more effective to intervene from infancy to establish weight control. Legally required health checkups in infants of 18 and 36 months present important opportunities for obesity prevention. We consider genetic analysis to be a very important factor for obesity prevention in infancy. However, since health checkups don't involve the collection of blood, genetic analysis is considered difficult. In this study, we attempted the typing of beta3 adrenergic receptor gene polymorphism as a genetic factor from non-invasively obtained samples, buccal mucosa, hair and cerumen in 96 infants at their 18- and 36-month health checkups. Sampling buccal mucosa, hair and cerumen instead of blood caused almost no anxiety to the child or parent, so 94.1% cooperation with sampling was obtained. From buccal mucosa, about 76% of the samples could be used for the typing of polymorphism (81% by enzyme method, 59% by kit method). From hair, about 44% of the samples permitted typing of polymorphism, but from cerumen only about 4% of the samples could be used. Results from buccal mucosa and hair typed about 90% of infant polymorphism. These results suggest that this method would be practical at periodic health checkups, and would probably be applicable to mass screenings for genetic factor analysis for other diseases.