An epidemiologic study of oral clefts in Iran: analysis of 1,669 cases.

OBJECTIVE

The objective of this study was to assess the epidemiology and some genetic aspects of oral clefting in Iran.

DESIGN

The study was a 15-year cross-sectional (prevalence) study from August 1976 to September 1991.

SETTING

The setting for the study was two plastic surgery departments, both mostly referral centers, and a maternity hospital in Iran.

PARTICIPANTS

The participants were 1,669 consecutive surgical cases with oral clefts (79% between 1 day and 18 months of age), registered in two centers. In a parallel study, 19,369 livebirths born in a maternity hospital within the same period were surveyed to ascertain prevalence of clefting at birth. Normal children of this population were used as the control group. Samples were analyzed by prevalence of clefting at birth, type of oral cleft, side of clefting, sex ratio, associated malformations, clefts in relatives, and parental consanguinity.

RESULTS

The prevalence of clefts was 1.03 per 1,000 births. Cleft lip (without cleft palate) had a higher (34.9%) and cleft palate alone had a significantly lower prevalence (17.4%) than expected. Cleft lip (without cleft palate) was more common in females (53.6%) than in males (46.4%). The rate of associated malformations in cleft patients (7.73%) was higher than in controls (0.093%). Association between clefting and consanguinity was significant (45.8% in cases versus 43.1% in controls). Occurrence of noncleft congenital malformations among first-degree relatives of our cases (2.77%) was nearly two times that of controls (1.55%).

CONCLUSION

Our study reveals that the population incidence of oral clefts in Iran is much closer to European than Arab-African or South East Asian countries. However, significant variations in other epidemiologic and some genetic features were observed.