Two Cases of ASXL3-Related Bainbridge-Ropers Syndrome: Clinical and Genetic Evaluation.

ASXL3-related disorder, also known as Bainbridge-Ropers syndrome (BRPS), is a neurodevelopmental condition first described by Bainbridge et al. and characterized by delayed psychomotor development, learning difficulties, characteristic craniofacial features, hypotonia, behavioral problems, and feeding problems. It is associated with heterozygous truncating pathogenic variants in the ASXL3 gene, located at chromosomal region 18q12.1. In this study, exome sequencing was performed in a 7-month-old male and a 4-year-old female patient who presented with unexplained developmental delay. De novo truncating variants in the ASXL3 gene were identified in both patients. Genetic analysis revealed that Patient 1 had a canonical splice-site likely pathogenic variant in the ASXL3 gene c.3039 + 1G > A. Patient 2 had a pathogenic variant in the ASXL3 gene c.1864_1867dup; p.Thr623Metfs∗25. We compared the patients' physical examination findings, clinical characteristics, and genetic results with those reported in the literature. This case report emphasizes the phenotypic spectrum of this disorder and describes a variant that, to our knowledge, has not been previously reported in the literature.