Spondyloepimetaphyseal dysplasia (SEMD), RPL13-related is caused by heterozygous variants in RPL13, which encodes the ribosomal protein eL13, a component of the 60S human ribosomal subunit. Here, we describe the clinical and radiological evolution of 11 individuals, 7 children and 4 adults, from 6 families. Some of the skeletal features improved during the course of this condition, whilst others worsened. We describe for the first time "corner fractures" as a feature of this dysplasia which as with other dysplasias disappear with age. In addition, we review the heights and skeletal anomalies of these reported here and previously in a total of 25 individuals from 15 families. In this study, six different RPL13 variants were identified, five of which were novel. All were located in the apparently hotspot region, located in intron 5 and exon 6. Splicing assays were performed for two of the three previously undescribed splicing variants. Until now, all splice variants have occurred in the intron 5 splice donor site, incorporating an additional 18 amino acids to the mutant protein. Here, we report the first variant in intron 5 splice acceptor site which generates two aberrant transcripts, deleting the first three and four amino acids encoded by exon 6. Thus, this study doubles the number of SEMD-RPL13-related cases and variants reported to date and describes unreported age-related clinical and radiological features.
Keywords: RPL13; skeletal dysplasia; spondyloepimetaphyseal dysplasia (SEMD).
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