Project description:Kleefstra syndrome, a disease with intellectual disability, autism spectrum disorders and other developmental defects is caused in humans by haploinsufficiency of EHMT1. Although EHMT1 and its paralog EHMT2 were shown to be histone methyltransferases responsible for deposition of the di-methylated H3K9 (H3K9me2), the exact nature of epigenetic dysfunctions in Kleefstra syndrome remains unknown. Here, we found that the epigenome of Ehmt1+/- adult mouse brain displays a marked increase of H3K9me2/3 which correlates with impaired expression of protocadherins, master regulators of neuronal diversity. Increased H3K9me3 was present already at birth, indicating that aberrant methylation patterns are established during embryogenesis. Interestingly, we found that Ehmt2+/- mice do not present neither the marked increase of H3K9me2/3 nor the cognitive deficits found in Ehmt1+/- mice, indicating an evolutionary diversification of functions. Our finding of increased H3K9me3 in Ehmt1+/- mice is the first one supporting the notion that EHMT1 can quench the deposition of tri-methylation by other Histone methyltransferases, ultimately leading to impaired neurocognitive functioning. Our insights into the epigenetic pathophysiology of Kleefstra syndrome may offer guidance for future developments of therapeutic strategies for this disease.
Project description:Potocki-Shaffer syndrome (PSS) is a rare contiguous gene deletion syndrome marked by haploinsufficiency of genes in chromosomal region 11p11.2p12. Approximately 50 cases of PSS have been reported; however, a syndrome with a PSS-like clinical phenotype caused by 11p11.12p12 duplication has not yet been reported. We first report the 11p11.12p12 duplication in a family with intellectual disability and craniofacial anomalies. 11p11.12p12 duplication syndrome was identified by karyotype analysis. Next-generation sequencing (NGS) analysis clarified the location of the chromosomal variations, which was confirmed by chromosome microarray analysis (CMA). Whole-exome sequencing (WES) was performed to exclude single nucleotide variations (SNVs). The raw data of NGS analysis and WES have been submitted to SRA, the accession number is PRJNA713823.
Project description:Haploinsufficiency of the Euchromatin histone methyltransferase 1 (EHMT1) gene leads to Kleefstra Syndrome, a rare disease characterised by moderate to severe developmental delay/intellectual disability, childhood hypotonia and distinct facial features, comprising microcephaly. This study examines the genetic variant EHMT1_Ter (p.[Tyr1148=];[Tyr1148Leufs*9]) in HEK293 cells.
2020-09-04 | GSE157390 | GEO
Project description:Germline variants in KMT2C inpatients with Kleefstra syndrome
Project description:Routine karyotyping combined with CMA testing should be provided for fetuses with omphalocele. WES is an option if karyotype and CMA tests are normal. In addition, if conventional karyotype, CMA detection and WES detection are normal, then further molecular biology methods can be used to rule out disease phenotypes like BWS syndrome. We analyzed the ultrasonographic features, genetic characteristics, and maternal and fetal outcomes of fetuses with omphalocele and provide a reference for perinatal management of such cases.
Project description:Over 400 million people worldwide are living with a rare disease, with genetic variants determining 80% of cases. Next Generation Sequencing identifies potential disease causative genetic variants, however many of these are classified as variants of uncertain significance (VUS). Each VUS requires functional validation as pathogenic or benign in disease pathology in specialist laboratories creating major delays in patient diagnosis. In this study we test a rapid genetic variant assessment pipeline using an EHMT1 (Euchromatin histone methyltransferase 1; EHMT1 p.Gln1144Ter) genetic variant that is pathogenic for Kleefstra Syndrome. Precise CRISPR homology directed (HDR) gene editing introduced the single nucleotide genetic variant in iPS cells and EHMT1_SNV cell clones were rapidly identified with amplicon sequencing. Induction of neural differentiation and RNA sequencing determined differences in differentiation at the gene and transcription factor level. The applied CRISPR HDR methodology was rapid and reliable for the introduction of SNVs in iPSCs for subsequent neuronal cell differentiation. Key features of Kleefstra Syndrome were identified, with involvement of key transcription factors REST and SP1 in disease mechanisms. This study indicates that precise iPSC gene editing and changes in disease modelling pathways can contribute to disease diagnosis and understanding of mechanisms.
2021-06-23 | GSE178646 | GEO
Project description:WES of Morquio A Syndrome Patient
