U2AF2 and Global developmental delay: Guided by these functional data, and in particular our results showing that RBFOX1 acted as a potential substrate and downstream effector of spliceosome malfunction, reanalysis of clinical negative exome data indeed revealed a de novo variant (c.353G>A, p.Arg118Gln) in RBFOX1 (NM_018723.4; OMIM 605104) in a patient with mild global developmental delay, hypotonia, ataxic gait, delayed myelination, and brain frontal volume loss, overlapping with the clinical symptoms observed in patients with U2AF2 variants.