Demographics of consanguinity in Palestinians with orofacial clefts: a non-randomised longitudinal study

Orofacial clefts (OFCs) are the most common craniofacial malformation at birth worldwide, with an incidence of 1·05 out of 1000 live births in the occupied Palestinian territory. The majority of OFCs present as singletons (without a family history of clefts), and a minority present as multiplex cases (greater than one OFC in the family). Consanguineous marriages (marriage between blood relatives) among Palestinians is approximately 40%. This study aims to define the incidence and impact of multiplicity in Palestinians with OFC, and to determine how his may be related to rates of consanguinity. We conducted a non-randomised longitudinal study using a 700-question survey administered in colloquial Arabic to mothers of patients with congenital anomalies (including patients with any craniofacial anomaly). Volunteer researchers fluent in English and Arabic were trained to recruit participants and administer surveys during craniofacial surgery screening events in Palestinian Government Hospitals. Selection criteria were a child in the family with an orofacial cleft, and family consent for participation in the survey. In a non-probability sampling method, the frequency of OFC in immediate and distant family members, and the extent of consanguineous marriages, were documented. Comparisons were made using chi squared tests; p