Degenerated hair follicle cells and partial loss of sebaceous and eccrine glands in a familial case of axenfeld-rieger syndrome: An emerging role for the FOXC1/NFATC1 genetic axis

Background: Cutaneous malformations are at times associated with some forms of congenital heart defects. Many a times subtle cutaneous phenotypes maybe overlooked as their significance on the lives of individuals is minimal. Lebanon represents an area of high consanguinity, where the rates can go beyond 70% in some districts. For the past 6 years, we have been studying several genodermatoses in Lebanon including those with cardiac malformations. Objectives: The main aim of this study is to document the genetic basis of a familial case of Axenfeld-Rieger Syndrome (ARS) with a mild cutaneous phenotype represented histologically with degeneration/ absence of hair follicles and incomplete formation of sebaceous and eccrine glands, in addition to the cardiac and ocular phenotypes. Methods: Whole exome sequencing was performed on two identical-twins with ARS along with their affected father and non-affected mother. Sanger sequencing was used to confirm the mutation, and the effects of the mutations on protein function was assessed in vitro using transient transfections. Results: A novel mutation inFOXC1 designated p.L240Rfs*75 was found in both twins and their father. The affected individuals share also a rare documented variant in NFATC1 designated p.V197 M. Both were absent from 200 Lebanese exomes. Our in vitro results suggested a gain of function activity of the FOXC1/NFATC1 complex, confirming its documented role in controlling murine hair follicle stem cells quiescence and regeneration. Conclusion: This is the first documented human case with a mutation inFOXC1 regulating multi-organ developmental pathways that reflect a conserved mechanism in cell differentiation and proliferation.