De novo missense variants in the RPEL3 domain of PHACTR4 in individuals with overlapping congenital anomalies

Abstract

PHACTR4 is proposed to play a role in embryonic development but has yet to be associated with human disease. Here, we report the detailed clinical features of two individuals for whom molecular diagnostic testing was undertaken at a large diagnostic laboratory and who were found to harbor rare, damaging de novo missense variants in the conserved RPEL3 domain of PHACTR4. We also present aggregate information on additional individuals in whom missense variants in the same PHACTR4 gene region were detected. All presented with overlapping phenotypes. Features present in at least half of these individuals included cleft palate, ophthalmologic abnormalities, hearing impairment, dysmorphic facial features, digital anomalies, renal/urinary anomalies, growth delay, microcephaly, abnormal brain imaging, and neurodevelopmental abnormalities; some individuals had additional unique findings as well. The proposed cellular function of PHACTR4 and information from related genes with variants in an RPEL domain suggest that PHACTR4 is a promising candidate gene for human disease. We hope that this report will promote additional research interest in the PHACTR4 gene and lead to the publication of additional cases, to potentially establish a causative relationship and to further delineate the phenotypic and variant spectrum of a PHACTR4-related disorder.

Keywords: PHACTR4, RPEL domain, G-actin, clinical exome sequencing, neurodevelopmental disorder, congenital anomalies, craniofacial anomalies, candidate gene, gene discovery.