Differences in the Reported Frequencies of Cleft Lip Plus Cleft Lip and Palate in Asians Born in Hawaii and the Continental United States 1

Abstract

Abstract

The etiology of cleft lip with or without cleft palate (CL/CP) is not known but present evidence suggests that both genetic and environmental factors act to determine susceptibility. Race has been reported to exert a strong influence on the incidence of CL/CP; e.g., the frequency of CL/CP is nearly twice as high among Japanese born in Japan or Hawaii as it is among Caucasians in Hawaii, Western Europe, and North America, and the risk in American blacks is one-half that in Caucasians. This notwithstanding, a survey of Los Angeles Hospitals and Clinics for families with facial clefting revealed no Orientals despite the fact that this group constitutes 6% of the population. To investigate the possibility that the rate of clefting had declined in Orientals'data was obtained from birth certificates from Hawaii, California, and New York, and from the USPHS Birth Defects Monitoring Program. The results suggest that the frequency of CL/CP but not isolated CP may be significantly lower among Japanese and other Orientals born in California and New York than among those born in Japan or Hawaii. This implies that environmental factors play a major role in determining the frequency of CL/CP in this racial group in the Orient and Hawaii.