Project description:<p>Our goal is to find genetic modifiers of major phenotypes in patients with 22q11.2 deletion syndrome, also known as DiGeorge syndrome or velo-cardio-facial syndrome. Whole exome sequencing was performed as part of a contract to the NHLBI, Resequencing and Genotyping Service. We have obtained cardiac phenotype information from the de-identified subjects enrolled in the study, either by echocardiography report or medical doctor report. All of the subjects have a 3 million base pair 22q11.2 deletion flanked by low copy repeats, LCR22, A-D.</p>
Project description:The 22q11.2 deletion syndrome (22q11.2DS) is the most common copy number variant (CNV)-associated syndrome, leading to congenital and neuropsychiatric anomalies. Patient-derived, induced pluripotent stem cell (iPS) models have provided important insight into the mechanisms of phenotypic features of this condition. However, patient-derived iPSC models may harbor underlying genetic heterogeneity that can confound analysis of pathogenic CNV effects. Furthermore, the ~1.5 Mb “A-B” deletion at this locus is inherited at higher frequency than the more common ~2.7 Mb “A-D” deletion, but remains under-studied due to lack of relevant models. To address these issues, here we leveraged a CRISPR-based strategy in Cas9-expressing iPS cells to engineer novel isogenic models of the 22q11.2 “A-B” deletion. After in vitro differentiation to excitatory neurons, integrated transcriptomic and cell surface proteomics identified deletion-associated alterations in surface adhesion markers. Furthermore, implantation of iPS-derived neuronal progenitor cells into the cortex of neonatal mice found decreased proliferation and accelerated neuronal maturation within a relevant microenvironment. Taken together, our results suggest potential pathogenic mechanisms of the 22q11.2 “A-B” deletion in driving neuronal and neurodevelopmental phenotypes. We further propose that the isogenic models generated here will provide a unique resource to study this less-common variant of the 22q11.2 microdeletion syndrome.
Project description:The 22q11.2 deletion syndrome (22q11.2DS) is the most common copy number variant (CNV)-associated syndrome, leading to congenital, cognitive, and neuropsychiatric anomalies in patients. The clinical presentation of the disease phenotypes is variable, posing significant challenges for prognosis of inheritance risk and clinical outcomes for the CNV carriers. ~85% of patients and almost all available human-centered models of this condition reflect the ~2.7 Mb “A-D” deletion at this locus. Leveraging a CRISPR/Cas9-based engineering strategy and induced pluripotent stems cells, we generated novel isogenic models for the smaller, commonly inherited 1.5 Mb “A-B” deletion found in ~5-10% of 22q11.2DS patients. The bulk RNA-seq data included here reflects paired-end 100 bp sequencing of iPSC-derived neuronal progenitor cells and excitatory neurons. These data reflect three independent clones either carrying the designed 22q11.2 deletion or control comparators (2 clones nucleofected with same sgRNA but with no deletion generated; 1 clone derived from the parental Cas9-expressing iPSC line). We anticipate that these novel, isogenic models will carry significant utility for the study of 22q11.2 deletion syndrome.
Project description:Approximately 60-70% of patients with 22q11.2 deletion syndrome (22q11.2DS; velo-cardio-facial syndrome/DiGeorge syndrome) have cardiac outflow tract anomalies including persistent truncus arteriosus (PTA) as the most severe defect. Among the genes in the 22q11.2 region, TBX1, encoding a T-box transcription factor is a major candidate for cardiovascular malformations and its inactivation in mice results in a PTA. To identify novel signaling mechanisms that function downstream, we found that Tbx1 restricts canonical Wnt signaling in the pharyngeal apparatus. To test for tissue specificity within the pharyngeal apparatus, we inactivated Tbx1 in the anterior portion of the secondary heart field (AHF) mesoderm using the Mef2c-AHF-Cre allele and observed a full penetrant PTA (n = 30). Tbx1 promotes progenitor cells but restricts differentiation whereas Wnt signaling, in the AHF, promotes cardiomyocyte differentiation. To determine whether Tbx1 and canonical Wnt signaling act in opposing pathways, both alleles of Tbx1 and one β-catenin allele were inactivated in the AHF and 85% of them (n = 35) showed partial or complete rescue. The antagonistic function of the two pathways was further confirmed by gene expression profiling, indicating that these two pathways provide a key balance in the AHF to prevent premature differentiation of progenitor cells prior to reaching the cardiac outflow tract. We inactivatedTbx1 and beta-catenin allele to identify function of Tbx1 and beta-catenin in the anterior portion of the secondary heart field (AHF) mesoderm. We also inactivated both alleles of Tbx1 and one β-catenin alleles (rescue design) to determine whether Tbx1 and canonical Wnt signaling act in opposing pathways
Project description:Approximately 60-70% of patients with 22q11.2 deletion syndrome (22q11.2DS; velo-cardio-facial syndrome/DiGeorge syndrome) have cardiac outflow tract anomalies including persistent truncus arteriosus (PTA) as the most severe defect. Among the genes in the 22q11.2 region, TBX1, encoding a T-box transcription factor is a major candidate for cardiovascular malformations and its inactivation in mice results in a PTA. To identify novel signaling mechanisms that function downstream, we found that Tbx1 restricts canonical Wnt signaling in the pharyngeal apparatus. To test for tissue specificity within the pharyngeal apparatus, we inactivated Tbx1 in the anterior portion of the secondary heart field (AHF) mesoderm using the Mef2c-AHF-Cre allele and observed a full penetrant PTA (n = 30). Tbx1 promotes progenitor cells but restricts differentiation whereas Wnt signaling, in the AHF, promotes cardiomyocyte differentiation. To determine whether Tbx1 and canonical Wnt signaling act in opposing pathways, both alleles of Tbx1 and one β-catenin allele were inactivated in the AHF and 85% of them (n = 35) showed partial or complete rescue. The antagonistic function of the two pathways was further confirmed by gene expression profiling, indicating that these two pathways provide a key balance in the AHF to prevent premature differentiation of progenitor cells prior to reaching the cardiac outflow tract.
Project description:<p>Two subjects with 22q11.2 deletion syndromes (22q11DS) and their parents were recruited for a whole genome sequencing study to identify candidate genetic modifiers of the various phenotypes seen in 22q11DS. Both probands had a typical 3 megabase deletion on chromosome 22q11.2 but discordant phenotypes.</p>
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.