Genetic analysis and prenatal diagnosis for a Chinese pedigree affected with Bainbridge-Ropers syndrome

Abstract

To explore the clinical features and genetic basis for a child with Bainbridge-Ropers syndrome (BRPS). Clinical data of the child were retrospectively analyzed. Copy number variation sequencing (CNV-seq) and trio based whole exome sequencing (trio-WES) were carried out. Prenatal diagnosis was provided for a at risk fetus from the pedigree, and genotype phenotype correlation was summarized through a literature review. The proband, a 6-year-old boy, has presented with feeding difficulties, specific craniofacial features, global developmental delay and intellectual disability, which has not improved after rehabilitation treatment. CNV-seq analysis of the patient showed no obvious abnormalities. A de novo heterozygous truncating variation, c.1448dupT (p.T484Nfs*5), was identified in the ASXL3 gene by trio-WES, which was a previously reported pathogenic variant. So far 14 Chinese patients with BRPS and ASXL3 variants have been reported. All patients have shown specific craniofacial features and delayed motor and speech development, and harbored 12 loss of function ASXL3 variants, which were de novo in origin and have clustered in exons 11 and 12 of the ASXL3 gene. The heterozygous frameshift c.1448dupT (p.T484Nfs*5) variant of the ASXL3 gene probably underlay the disorder in this patient. BRPS should be considered in infants with feeding difficulties, special craniofacial features, global developmental delay and hand anomalies, and WES can help to delineate the pathogenesis and establish the definite diagnosis.