Biallelic variants in RBM42 cause a multisystem disorder with neurological, facial, cardiac, and musculoskeletal involvement

Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of RBM42 with hnRNP K, which is the causative gene for Au-Kline syndrome with overlapping disease characteristics seen in the index patient. The human R102* or A438T mutant protein failed to fully rescue the growth defects of RBM42 ortholog knockout ΔFgRbp1 in Fusarium while it was rescued by the wild-type (WT) human RBM42. A mouse model carrying Rbm42 compound heterozygous variants, c.280C>T (p.Q94*) and c.1306_1308delinsACA (p.A436T), demonstrated gross fetal developmental defects and most of the double mutant animals died by E13.5. RNA-seq data confirmed that Rbm42 was involved in neurological and myocardial functions with an essential role in alternative splicing (AS). Overall, we present clinical, genetic, and functional data to demonstrate that defects in RBM42 constitute the underlying etiology of a new neurodevelopmental disease which links the dysregulation of global AS to abnormal embryonic development.

Prenatal diagnosis of spinal muscular atrophy using multiple ligation-dependent probe amplification / 中华医学遗传学杂志

OBJECTIVE@#To carry out prenatal diagnosis for families with high risk for spinal muscular atrophy (SMA) by using multiplex ligation-dependent probe amplification (MLPA).@*METHODS@#Twenty-one families were enrolled. MLPA was used to detect copy numbers of SMN1 and SMN2 genes. Maternal contamination was excluded by using a short tandem repeat method.@*RESULTS@#For 23 fetuses from the 21 families, 14 were identified as carriers, 1 as SMA patient, and 8 as normal. By linkage analysis of parental samples, three individuals were determined as silent (2+0) carriers.@*CONCLUSION@#MLPA can determine the carrier status of SMA. The identification of three silent (2+0) carriers among the 44 parental samples indicated a risk for such families, for which genetic counseling and reproduction guidance should be provided.