ABSTRACT Silver–Russell Syndrome (SRS) is a genetic disorder characterized by intrauterine and postnatal growth restriction. Most cases are caused by an imprinting error either with hypomethylation of the Imprinted Control Region 1 at 11p15.5, or maternal uniparental disomy of chromosome 7. Approximately 40% of the cases have unknown etiology, thus distinct mechanisms have been described in association with the syndrome. Here, we present a case of monozygotic twin sisters with a clinical diagnosis of SRS, mild intellectual disability and epilepsy who carry a balanced translocation between chromosomes 3 and 12 that interrupts the NAALADL2 and HMGA2 genes, respectively. Disruption of HMGA2 , a gene previously described as causative of SRS, confirms the initial diagnosis. NAALADL2 gene has been recently proposed as a candidate for intellectual disability and could partially contribute to our patient's phenotype.
Abstract Mohr-Tranebjærg syndrome is an X-linked syndrome characterized by sensorineural hearing impairment in childhood, followed by progressive neurodegeneration leading to a broad phenotypic spectrum. Genetically MTS is caused by pathogenic variants in the TIMM8A gene, including gene deletions and larger contiguous gene deletions. Some of the latter involve the neighboring gene BTK , resulting in agammaglobulinemia. By next‐generation mate‐pair sequencing we have mapped the chromosomal deletion breakpoints of one MTS case and three XLA-MTS cases and used breakpoint-spanning PCR to fine map the breakpoints by Sanger sequencing. Two of the XLA-MTS cases presented with large deletions (63.5 and 27.2 kb), and the junctional regions were characterized by long stretches of microhomology, indicating that the events have emerged through homologous recombination. Conversely, the MTS case exhibited a small 2 bp region of microhomology, and the regions were not characterized by extensive microhomology. The third XLA-MTS case had a more complex breakpoint, including a 59 bp inverted insertion, thus at least four breakpoints were involved in this event. In conclusion, mate-pair library generation combined with next-generation sequencing is an efficient method for breakpoint identification, also in regions characterized by repetitive elements.
Metadata and statistics of integrative ChIP-seq and expression analysis. This file contains three Excel spreadsheets. Spreadsheet 1 contains information on the number of genes common to both the exon expression array and ChIPseq analyses. Spreadsheets 2 and 3 include statistical and permutation tests concerning enrichment of DEGs among BRD1 PTGs. (XLSX 12 kb)
Elucidating the molecular mechanisms that regulate human stromal (mesenchymal) stem cell (hMSC) differentiation into osteogenic lineage is important for the development of anabolic therapies for treatment of osteoporosis. MicroRNAs (miRNAs) are short, noncoding RNAs that act as key regulators of diverse biological processes by mediating translational repression or mRNA degradation of their target genes. Here, we show that miRNA-138 (miR-138) modulates osteogenic differentiation of hMSCs. miRNA array profiling and further validation by quantitative RT-PCR (qRT-PCR) revealed that miR-138 was down-regulated during osteoblast differentiation of hMSCs. Overexpression of miR-138 inhibited osteoblast differentiation of hMSCs in vitro, whereas inhibition of miR-138 function by antimiR-138 promoted expression of osteoblast-specific genes, alkaline phosphatase (ALP) activity, and matrix mineralization. Furthermore, overexpression of miR-138 reduced ectopic bone formation in vivo by 85%, and conversely, in vivo bone formation was enhanced by 60% when miR-138 was antagonized. Target prediction analysis and experimental validation by luciferase 3′ UTR reporter assay confirmed focal adhesion kinase, a kinase playing a central role in promoting osteoblast differentiation, as a bona fide target of miR-138. We show that miR-138 attenuates bone formation in vivo, at least in part by inhibiting the focal adhesion kinase signaling pathway. Our findings suggest that pharmacological inhibition of miR-138 by antimiR-138 could represent a therapeutic strategy for enhancing bone formation in vivo.
