Oral clefts in the Sultanate of Oman

Abstract

This is a retrospective study of the epidemiology of congenital clefts of the lip and palate in babies of Omani nationals born in the Sultanate of Oman between 1989 and 1995. Babies of non-Omani immigrants were excluded from the study. The data were collected from two sources. The first was the Centralized Plastic Surgery Service of Khoula Hospital at Muscat, the capital city of Oman between 1989 and 1995, which registers all oral cleft cases in the country. These data revealed the overall incidence of oral clefts (OC) to be 1.5 per 1000 live births, with incidences of 0.62 per 1000 for combined lip and palate (CLP) cleft, 0.34 per 1000 for cleft lip (CL), and 0.54 per 1000 for isolated cleft palate (CP). The second data source was national delivery records from maternity sections of all hospitals in the country from 1989 to 1995, which include oral clefts as congenital anomalies identified at birth. These statistics were similar to those from the first source for CL/CLP but underestimated the number of isolated cleft palates (CP). The histories of patients attending the Plastic Surgery Clinic of Khoula Hospital during the last year of the study period could be examined in detail. A study of the 177 OC cases registered in 1995 alone revealed associated congenital anomalies in 38.4%. A higher inbreeding coefficient of 0.0294 was noted among oral cleft cases than in the general population, which was calculated at 0.0198. Familial clefts accounted for 23% of all cases. Greater parental age and birth order were found to be associated with increased risk of oral cleft. High temperatures during the tropical desert summers in Oman (when temperatures reach 48°C) do not seem related to the incidence of oral clefts.