The impact of family history of non-syndromic oral clefts on their incidence in pregnancy.

Background and objective: Orofacial clefts are the most commonly diagnosed birth defects of the face during pregnancy. They can be either syndromic or non-syndromic. The objective of this study was to calculate the incidence of non-syndromic cleft lip with or without cleft palate (CL/CP) and isolated cleft palate (CP) in patients with a positive family history of non-syndromic oral clefts, and to identify the familial risk factors of oral cleft development in these patients.Methods: This was a retrospective study that included all patients with a positive family history of non-syndromic oral clefts, followed up in the department of fetal medicine in Brugmann University Hospital, Brussels, Belgium, between 1 January 2009 and 31 December 2019.Results: Over the study period, the incidence of non-syndromic oral clefts was 10.81/10,000 pregnancies. Seventy-three (0.15%) women had a positive family history of oral clefts, and had 86 pregnancies during this period. The incidence of oral clefts in this group was 9.3% (86-fold increase). This incidence varied depending on many factors, including the type of oral clefts in the family, the degree of relation of the fetus or baby to the family member who has the cleft, and the number of siblings with oral clefts.Conclusion: The offspring of pregnant patients with a positive family history of oral clefts are at risk for recurrence. The incidence is very high when there are 3 or more siblings with oral clefts, when the father or mother has the anomaly, or when there is bilateral CL/CP in the family history.