Novel IRF6 variant in orofacial cleft patients from Durban, South Africa

Background: To date, there are over 320 variants identified in the IRF6 gene that cause Van der Woude syndrome or popliteal pterygium syndrome. We sequenced this gene in a South African orofacial cleft cohort to identify the causal IRF6 variants in our population.

Method: Saliva samples from 100 patients with syndromic and non-syndromic CL ± P were collected. Patients were recruited from the cleft clinics at two public, tertiary hospitals in Durban, South Africa (SA), namely Inkosi Albert Luthuli Central Hospital (IALCH) and KwaZulu-Natal Children's Hospital (KZNCH). We prospectively sequenced the exons of IRF6 in 100 orofacial cleft cases, and where possible, we also sequenced the parents of the individuals to determine the segregation pattern.

Results: Two variants were identified; one novel (p.Cys114Tyr) and one known (p.Arg84His) missense variant in IRF6 gene were identified. The patient with the p.Cys114Tyr variant was non-syndromic with no clinical VWS phenotype expected of individuals with IRF6 coding variants, and the patient with the p.Arg84His had phenotypic features of popliteal pterygium syndrome. The p.Arg84His variant segregated in the family, with the father also being affected.

Conclusions: This study provides evidence that IRF6 variants are found in the South African population. Genetic counselling is essential for affected families, particularly in the absence of a known clinical phenotype since it helps with the plans for future pregnancies.