Asian oral-facial cleft birth prevalence.

OBJECTIVE: To determine the clefting birth prevalence among Asian populations, specifically Chinese and Japanese, using raw counts from nonoverlapping published studies of Asian populations, and to investigate whether Asian clefting rates have been interpreted accurately as being up to twice the Caucasian rate.
DESIGN: A literature review of articles giving raw counts of clefting in Asian populations, primarily Japanese and Chinese. MAIN OUTCOME MEASURES: Where possible, clefts were identified by the patients' ethnicity, country of origin, cleft type, syndromic status, and birth status.
RESULTS: Prevalence rates of cleft lip with or without cleft palate per 1000 live births are reported. Syndromic plus nonsyndromic cleft lip with or without cleft palate: Chinese, 1.30; Japanese, 1.34; Other Asian, 1.47; and total, 1.33. Nonsyndromic cleft lip with or without cleft palate: Chinese, 1.20; Japanese, 1.18; Other Asian, 1.22; and total, 1.19.
CONCLUSIONS: Overall, Chinese and Japanese live birth prevalence rates for nonsyndromic cleft lip with or without cleft palate, based on the published reports of birth prevalence, are significantly lower than the oft-quoted rate of 2 per 1000 for Asians. The apparent reason for the discrepancy is that many published prevalence rates included all pregnancies (live births plus pregnancy losses) and do not distinguish between syndromic and nonsyndromic clefts or between cleft palate alone and cleft lip with or without cleft palate. These results demonstrate that it is extremely important for current population-based studies of clefts to include careful delineation of population groups, syndromes, cleft type, and birth status.