First nonsense variant of MED12 gene in a female with complete Maat-Kievit-Brunner phenotype of Ohdo syndrome: A case report

Abstract

BackgroundOhdo syndrome (OMIM≠ 249,620) is a clinically heterogeneous group of genetic disorders mainly characterized by intellectual disability, blepharophimosis and specific facial features. It comprises five distinct subtypes, each exhibiting unique clinical characteristics. Herein, we report a novel case of the Maat-Kievit-Brunner (OSMKB; X-linked recessive) subtype caused by a novel pathogenic MED12 nonsense variant, classically associated with missense variants of the MED12 gene (Xq13.1). Moreover, we conduct a comparative analysis of reported MED12 pathogenic variants in the literature. Case presentationOur patient is a five-year-old girl demonstrating a complete OSMKB phenotype. She exhibits all the characteristic features associated to this latter including intellectual disability, developmental delay, indicative dysmorphia featured by blepharophemosis and a triangular face, and hypotonia. Conclusionsclinical and molecular data of this rare case expands the clinical and genetic landscapes of MED12 gene which is considered important for establishing strong genotype-phenotype correlations as much as for genetic counselling.