Biallelic loss-of-function variants in <i>CACHD1 </i>cause a novel neurodevelopmental syndrome with facial dysmorphism and multisystem congenital abnormalities

Purpose We established the genetic etiology of a syndromic neurodevelopmental condition characterized by variable cognitive impairment, recognizable facial dysmorphism, and a constellation of extra-neurological manifestations. Methods We performed phenotypic characterization of 6 participants from 4 unrelated families presenting with a neurodevelopmental syndrome and used exome sequencing to investigate the underlying genetic cause. To probe relevance to the neurodevelopmental phenotype and craniofacial dysmorphism, we established two- and three-dimensional human stem cell-derived neural models and generated a stable cachd1 zebrafish mutant on a transgenic cartilage reporter line. Results Affected individuals showed mild cognitive impairment, dysmorphism featuring oculo-auriculo abnormalities, and developmental defects involving genitourinary and digestive tracts. Exome sequencing revealed biallelic putative loss-of-function variants in CACHD1 segregating with disease in all pedigrees. RNA sequencing in CACHD1-depleted neural progenitors revealed abnormal expression of genes with key roles in Wnt signaling, neurodevelopment, and organ morphogenesis. CACHD1 depletion in neural progenitors resulted in reduced percentages of post-mitotic neurons and enlargement of 3D neurospheres. Homozygous cachd1 mutant larvae showed mandibular patterning defects mimicking human facial dysmorphism. Conclusion Our findings support the role of loss-of-function variants in CACHD1 as the cause of a rare neurodevelopmental syndrome with facial dysmorphism and multisystem abnormalities

Association study of selected polymorphisms of DNMT3A and DNMT3B genes with panic disorder

Currently, the vulnerability-stress model, in the sense of a multifactorial explanatory model, is considered to be the most appropriate to represent the etiopathogenesis of anxiety disorders. Epigenetic mechanisms are understood as a bridge between genetic factors and environmental factors. This includes the methylation of specific DNA regions, which is mediated by DNA methyltransferases. These enzymes have rarely been the focus of psychiatric research in relation to anxiety disorders. Therefore, this work deals with selected single nucleotide polymorphisms of the DNMT3A and DNMT3B gene and investigates whether these SNPs and/or their haplotypes are associated panic disorder and/or with dimensional psychological characteristics, such as anxiety-related cognition or anxiety sensitivity. In summary, a significant or nominally significant association of two SNPs with anxiety-related characteristics such was shown. To better assess these associations, replications with sufficient test strength are required . Given the demonstrated association with PSWQ, investigation of another anxiety phenotype, Generalized Anxiety Disorder, is also sensible. As a further step, the functionality of the significantly associated SNPs should be performed. In addition, another DNMT, Dnmt1, is associated with fear conditioning, and the methylation patterns of the DNMTs themselves also appear to have an impact on the development of anxiety disorders. Therefore, an investigation of the DNMT1 gene and the methylation patterns of the DNMT genes are further reasonable steps to better understand a possible influence of DNMTs on the development of anxiety disorders and on anxiety-related psychological characteristics.Derzeit gilt das Vulnerabilitäts-Stressmodell im Sinne eines multifaktoriellen Erklärungsmodells als am besten geeignet, um die Ätiopathogenese der Angsterkrankungen abzubilden. Als Brücke zwischen den genetischen Faktoren und den auf ein Individuum einwirkenden Umweltfaktoren werden epigenetische Mechanismen verstanden. Hierzu zählt die Methylierung bestimmter DNA-Bereiche, welche durch die DNA-Methyltransferasen vermittelt wird. Diese Enzyme waren in Verbindung mit Angsterkrankungen bisher kaum im Fokus psychiatrischer Forschung. Diese Arbeit beschäftigt sich daher mit ausgewählten Einzelnukleotidpolymorphismen des DNMT3A- und DNMT3B-Gens und untersucht, ob diese SNPs und/oder deren Haplotypen zum einen mit der Panikstörung und zum andern mit dimensionalen psychologischen Charakteristiken, wie angstbezogener Kognition oder Angstsensitivität, assoziiert sind. Zusammenfassend konnte eine signifikante bzw. nominal signifikante Assoziation der zweier SNPs mit angstbezogenen Charakteristiken wie der angstbezogenen Kognition und der Angstsensitivität gezeigt werden. Um die gefundenen Assoziationen besser beurteilen zu können, ist in Folgeuntersuchungen eine Replikation in einer weiteren Probandengruppe und in einer angemessen großen Patienten- und Fall-Kontroll-Gruppe mit ausreichender Teststärke erforderlich. Aufgrund der nachgewiesenen Assoziation mit dem PSWQ bietet sich auch die Untersuchung eines anderen Angstphänotypen, der Generalisierten Angststörung, an. Als weiterer Schritt sind Untersuchungen zur Klärung der Funktionalität der signifikant assoziierten SNPs anzustreben. In der Literatur wird zudem eine weitere DNMT, die Dnmt1, mit der Furchtkonditionierung assoziiert und auch die Methylierungsmuster der DNMTs selbst scheinen einen Einfluss auf die Entwicklung von Angststörungen zu haben. Eine Untersuchung des DNMT1-Gens und der Methylierungsmuster der DNMT-Gene sind daher weitere sinnvolle Schritte, um einen möglichen Einfluss von DNMTs auf die Entstehung von Angsterkrankungen und auf angstbezogene psychologische Charakteristiken besser zu verstehen

An investigation of genetic variability of DNA methyltransferasesDNMT3Aand3Bdoes not provide evidence for a major role in the pathogenesis of panic disorder and dimensional anxiety phenotypes

While DNA methylation patterns have been studied for a role in the pathogenesis of anxiety disorders, the role of the enzymes establishing DNA methylation-DNA methyltransferases (DNMTs)-has yet to be investigated. In an effort to investigate DNMT genotype-specific effects on dimensional anxiety traits in addition to the categorical phenotype of panic disorder, 506 panic disorder patients and 3112 healthy participants were assessed for anxiety related cognition [Agoraphobic Cognitions Questionnaire (ACQ)], anxiety sensitivity [Anxiety Sensitivity Index (ASI)] as well as pathological worry [Penn State Worry Questionnaire (PSWQ)] and genotyped for five single nucleotide polymorphisms (SNPs) in theDNMT3A(rs11683424, rs1465764, rs1465825) andDNMT3B(rs2424932, rs4911259) genes, which have previously been found associated with clinical and trait-related phenotypes. There was no association with the categorical phenotype panic disorder. However, a significant association was discerned betweenDNMT3Ars1465764 and PSWQ scores in healthy participants, with the minor allele conveying a protective effect. In addition, a marginally significant association between questionnaire scores (PSWQ, ASI) in healthy participants andDNMT3Brs2424932 was detected, again with the minor allele conveying a protective effect. The present results suggest a possible minor role ofDNMT3AandDNMT3Bgene variation in conveying resilience towards anxiety disorders. As the observed associations indicated a protective effect of two SNPs particularly with pathological worry, future studies are proposed to explore these variants in generalized anxiety disorder rather than panic disorder