scholarly journals De novo mutations in inhibitors of Wnt, BMP, and Ras/ERK signaling pathways in non-syndromic midline craniosynostosis

2017 ◽  
Vol 114 (35) ◽  
pp. E7341-E7347 ◽  
Author(s):  
Andrew T. Timberlake ◽  
Charuta G. Furey ◽  
Jungmin Choi ◽  
Carol Nelson-Williams ◽  
Erin Loring ◽  
...  
Keyword(s):  
De Novo ◽  
Erk Signaling ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Neurodevelopmental Outcomes ◽  
Locus Heterogeneity ◽  
Syndromic Craniosynostosis ◽  
New Genes ◽  
Morphogenetic Protein ◽  
Nuclear Targets

Non-syndromic craniosynostosis (NSC) is a frequent congenital malformation in which one or more cranial sutures fuse prematurely. Mutations causing rare syndromic craniosynostoses in humans and engineered mouse models commonly increase signaling of the Wnt, bone morphogenetic protein (BMP), or Ras/ERK pathways, converging on shared nuclear targets that promote bone formation. In contrast, the genetics of NSC is largely unexplored. More than 95% of NSC is sporadic, suggesting a role for de novo mutations. Exome sequencing of 291 parent–offspring trios with midline NSC revealed 15 probands with heterozygous damaging de novo mutations in 12 negative regulators of Wnt, BMP, and Ras/ERK signaling (10.9-fold enrichment, P = 2.4 × 10−11). SMAD6 had 4 de novo and 14 transmitted mutations; no other gene had more than 1. Four familial NSC kindreds had mutations in genes previously implicated in syndromic disease. Collectively, these mutations contribute to 10% of probands. Mutations are predominantly loss-of-function, implicating haploinsufficiency as a frequent mechanism. A common risk variant near BMP2 increased the penetrance of SMAD6 mutations and was overtransmitted to patients with de novo mutations in other genes in these pathways, supporting a frequent two-locus pathogenesis. These findings implicate new genes in NSC and demonstrate related pathophysiology of common non-syndromic and rare syndromic craniosynostoses. These findings have implications for diagnosis, risk of recurrence, and risk of adverse neurodevelopmental outcomes. Finally, the use of pathways identified in rare syndromic disease to find genes accounting for non-syndromic cases may prove broadly relevant to understanding other congenital disorders featuring high locus heterogeneity.

scholarly journals Mutations in TFAP2B and previously unimplicated genes of the BMP, Wnt, and Hedgehog pathways in syndromic craniosynostosis

2019 ◽  
Vol 116 (30) ◽  
pp. 15116-15121 ◽  
Author(s):  
Andrew T. Timberlake ◽  
Sheng Chih Jin ◽  
Carol Nelson-Williams ◽  
Robin Wu ◽  
Charuta G. Furey ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
De Novo ◽  
Neural Crest Cell ◽  
High Yield ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Syndromic Craniosynostosis ◽  
Mutation Burden ◽  
Genes Encoding ◽  
Genetic Evaluations

Craniosynostosis (CS) is a frequent congenital anomaly featuring the premature fusion of 1 or more sutures of the cranial vault. Syndromic cases, featuring additional congenital anomalies, make up 15% of CS. While many genes underlying syndromic CS have been identified, the cause of many syndromic cases remains unknown. We performed exome sequencing of 12 syndromic CS cases and their parents, in whom previous genetic evaluations were unrevealing. Damaging de novo or transmitted loss of function (LOF) mutations were found in 8 genes that are highly intolerant to LOF mutation (P = 4.0 × 10−8); additionally, a rare damaging mutation in SOX11, which has a lower level of intolerance, was identified. Four probands had rare damaging mutations (2 de novo) in TFAP2B, a transcription factor that orchestrates neural crest cell migration and differentiation; this mutation burden is highly significant (P = 8.2 × 10−12). Three probands had rare damaging mutations in GLI2, SOX11, or GPC4, which function in the Hedgehog, BMP, and Wnt signaling pathways; other genes in these pathways have previously been implicated in syndromic CS. Similarly, damaging de novo mutations were identified in genes encoding the chromatin modifier KAT6A, and CTNNA1, encoding catenin α-1. These findings establish TFAP2B as a CS gene, have implications for assessing risk to subsequent children in these families, and provide evidence implicating other genes in syndromic CS. This high yield indicates the value of performing exome sequencing of syndromic CS patients when sequencing of known disease loci is unrevealing.

scholarly journals Molecular Dissection of Neurodevelopmental Disorder-Causing Mutations in CYFIP2

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1355
Author(s):  
Matthias Schaks ◽  
Michael Reinke ◽  
Walter Witke ◽  
Klemens Rottner
Keyword(s):  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Small Gtpases ◽  
Normal Brain ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Neuronal Morphogenesis ◽  
Variable Extent ◽  
Regulatory Complex ◽  
Almost All

Actin remodeling is frequently regulated by antagonistic activities driving protrusion and contraction downstream of Rac and Rho small GTPases, respectively. WAVE regulatory complex (WRC), which primarily operates downstream of Rac, plays pivotal roles in neuronal morphogenesis. Recently, two independent studies described de novo mutations in the CYFIP2 subunit of WRC, which caused intellectual disability (ID) in humans. Although mutations had been proposed to effect WRC activation, no experimental evidence for this was provided. Here, we made use of CRISPR/Cas9-engineered B16-F1 cell lines that were reconstituted with ID-causing CYFIP variants in different experimental contexts. Almost all CYFIP2-derived mutations (7 out of 8) promoted WRC activation, but to variable extent and with at least two independent mechanisms. The majority of mutations occurs in a conserved WAVE-binding region, required for WRC transinhibition. One mutation is positioned closely adjacent to the Rac-binding A site and appears to ease Rac-mediated WRC activation. As opposed to these gain-of-function mutations, a truncating mutant represented a loss-of-function variant and failed to interact with WRC components. Collectively, our data show that explored CYFIP2 mutations frequently, but not always, coincide with WRC activation and suggest that normal brain development requires a delicate and precisely tuned balance of neuronal WRC activity.

scholarly journals SOX2 Plays a Critical Role in the Pituitary, Forebrain, and Eye during Human Embryonic Development

2008 ◽  
Vol 93 (5) ◽  
pp. 1865-1873 ◽  
Author(s):  
Daniel Kelberman ◽  
Sandra C. P. de Castro ◽  
Shuwen Huang ◽  
John A. Crolla ◽  
Rodger Palmer ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Anterior Pituitary ◽  
De Novo ◽  
Hypogonadotropic Hypogonadism ◽  
Expression Patterns ◽  
Critical Role ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Direct Role

Abstract Context: Heterozygous, de novo mutations in the transcription factor SOX2 are associated with bilateral anophthalmia or severe microphthalmia and hypopituitarism. Variable additional abnormalities include defects of the corpus callosum and hippocampus. Objective: We have ascertained a further three patients with severe eye defects and pituitary abnormalities who were screened for mutations in SOX2. To provide further evidence of a direct role for SOX2 in hypothalamo-pituitary development, we have studied the expression of the gene in human embryonic tissues. Results: All three patients harbored heterozygous SOX2 mutations: a deletion encompassing the entire gene, an intragenic deletion (c.70_89del), and a novel nonsense mutation (p.Q61X) within the DNA binding domain that results in impaired transactivation. We also show that human SOX2 can inhibit β-catenin-driven reporter gene expression in vitro, whereas mutant SOX2 proteins are unable to repress efficiently this activity. Furthermore, we show that SOX2 is expressed throughout the human brain, including the developing hypothalamus, as well as Rathke’s pouch, the developing anterior pituitary, and the eye. Conclusions: Patients with SOX2 mutations often manifest the unusual phenotype of hypogonadotropic hypogonadism, with sparing of other pituitary hormones despite anterior pituitary hypoplasia. SOX2 expression patterns in human embryonic development support a direct involvement of the protein during development of tissues affected in these individuals. Given the critical role of Wnt-signaling in the development of most of these tissues, our data suggest that a failure to repress the Wnt-β-catenin pathway could be one of the underlying pathogenic mechanisms associated with loss-of-function mutations in SOX2.

scholarly journals A de novo paradigm for male infertility

2021 ◽  
Author(s):  
MS Oud ◽  
RM Smits ◽  
HE Smith ◽  
FK Mastrorosa ◽  
GS Holt ◽  
...  
Keyword(s):  
Male Infertility ◽  
De Novo ◽  
P Value ◽  
Missense Mutations ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Systematic Analysis ◽  
Significant Enrichment

IntroductionDe novo mutations (DNMs) are known to play a prominent role in sporadic disorders with reduced fitness1. We hypothesize that DNMs play an important role in male infertility and explain a significant fraction of the genetic causes of this understudied disorder. To test this hypothesis, we performed trio-based exome-sequencing in a unique cohort of 185 infertile males and their unaffected parents. Following a systematic analysis, 29 of 145 rare protein altering DNMs were classified as possibly causative of the male infertility phenotype. We observed a significant enrichment of Loss-of-Function (LoF) DNMs in LoF-intolerant genes (p-value=1.00×10-5) as well as predicted pathogenic missense DNMs in missense-intolerant genes (p-value=5.01×10-4). One DNM gene identified, RBM5, is an essential regulator of male germ cell pre-mRNA splicing2. In a follow-up study, 5 rare pathogenic missense mutations affecting this gene were observed in a cohort of 2,279 infertile patients, with no such mutations found in a cohort of 5,784 fertile men (p-value=0.009). Our results provide the first evidence for the role of DNMs in severe male infertility and point to many new candidate genes affecting fertility.

scholarly journals Loss-of-Function GRHL3 Variants Detected in African Patients with Isolated Cleft Palate

2017 ◽  
Vol 97 (1) ◽  
pp. 41-48 ◽  
Author(s):  
M.A. Eshete ◽  
H. Liu ◽  
M. Li ◽  
W.L. Adeyemo ◽  
L.J.J Gowans ◽  
...  
Keyword(s):  
Cleft Palate ◽  
Cleft Lip ◽  
De Novo ◽  
Phosphorylation Site ◽  
Dominant Negative ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Sumoylation Site ◽  
Genetic Etiology

In contrast to the progress that has been made toward understanding the genetic etiology of cleft lip with or without cleft palate, relatively little is known about the genetic etiology for cleft palate only (CPO). A common coding variant of grainyhead like transcription factor 3 ( GRHL3) was recently shown to be associated with risk for CPO in Europeans. Mutations in this gene were also reported in families with Van der Woude syndrome. To identify rare mutations in GRHL3 that might explain the missing heritability for CPO, we sequenced GRHL3 in cases of CPO from Africa. We recruited participants from Ghana, Ethiopia, and Nigeria. This cohort included case-parent trios, cases and other family members, as well as controls. We sequenced exons of this gene in DNA from a total of 134 nonsyndromic cases. When possible, we sequenced them in parents to identify de novo mutations. Five novel mutations were identified: 2 missense (c.497C>A; p.Pro166His and c.1229A>G; p.Asp410Gly), 1 splice site (c.1282A>C p.Ser428Arg), 1 frameshift (c.470delC; p.Gly158Alafster55), and 1 nonsense (c.1677C>A; p.Tyr559Ter). These mutations were absent from 270 sequenced controls and from all public exome and whole genome databases, including the 1000 Genomes database (which includes data from Africa). However, 4 of the 5 mutations were present in unaffected mothers, indicating that their penetrance is incomplete. Interestingly, 1 mutation damaged a predicted sumoylation site, and another disrupted a predicted CK1 phosphorylation site. Overexpression assays in zebrafish and reporter assays in vitro indicated that 4 variants were functionally null or hypomorphic, while 1 was dominant negative. This study provides evidence that, as in Caucasian populations, mutations in GRHL3 contribute to the risk of nonsyndromic CPO in the African population.

scholarly journals Loss-of-function de novo mutations play an important role in severe human neural tube defects

2015 ◽  
Vol 52 (7) ◽  
pp. 493-497 ◽  
Author(s):  
Philippe Lemay ◽  
Marie-Claude Guyot ◽  
Élizabeth Tremblay ◽  
Alexandre Dionne-Laporte ◽  
Dan Spiegelman ◽  
...  
Keyword(s):  
Neural Tube ◽  
Neural Tube Defects ◽  
De Novo ◽  
Loss Of Function ◽  
De Novo Mutations

scholarly journals Unexpected role of SIX1 variants in craniosynostosis: expanding the phenotype of SIX1-related disorders

2021 ◽  
pp. jmedgenet-2020-107459
Author(s):  
Eduardo Calpena ◽  
Maud Wurmser ◽  
Simon J McGowan ◽  
Rodrigo Atique ◽  
Débora R Bertola ◽  
...  
Keyword(s):  
De Novo ◽  
Population Data ◽  
Cranial Sutures ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Data Enrichment ◽  
Whole Exome ◽  
Lambdoid Synostosis ◽  
Suture Fusion

BackgroundPathogenic heterozygous SIX1 variants (predominantly missense) occur in branchio-otic syndrome (BOS), but an association with craniosynostosis has not been reported.MethodsWe investigated probands with craniosynostosis of unknown cause using whole exome/genome (n=628) or RNA (n=386) sequencing, and performed targeted resequencing of SIX1 in 615 additional patients. Expression of SIX1 protein in embryonic cranial sutures was examined in the Six1nLacZ/+ reporter mouse.ResultsFrom 1629 unrelated cases with craniosynostosis we identified seven different SIX1 variants (three missense, including two de novo mutations, and four nonsense, one of which was also present in an affected twin). Compared with population data, enrichment of SIX1 loss-of-function variants was highly significant (p=0.00003). All individuals with craniosynostosis had sagittal suture fusion; additionally four had bilambdoid synostosis. Associated BOS features were often attenuated; some carrier relatives appeared non-penetrant. SIX1 is expressed in a layer basal to the calvaria, likely corresponding to the dura mater, and in the mid-sagittal mesenchyme.ConclusionCraniosynostosis is associated with heterozygous SIX1 variants, with possible enrichment of loss-of-function variants compared with classical BOS. We recommend screening of SIX1 in craniosynostosis, particularly when sagittal±lambdoid synostosis and/or any BOS phenotypes are present. These findings highlight the role of SIX1 in cranial suture homeostasis.

scholarly journals De novo mutations in childhood cases of sudden unexplained death that disrupt intracellular Ca2+ regulation

2021 ◽  
Vol 118 (52) ◽  
pp. e2115140118
Author(s):  
Matthew Halvorsen ◽  
Laura Gould ◽  
Xiaohan Wang ◽  
Gariel Grant ◽  
Raquel Moya ◽  
...  
Keyword(s):  
Sudden Death ◽  
Odds Ratio ◽  
Neuronal Excitability ◽  
De Novo ◽  
Sequence Data ◽  
Compound Heterozygous ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Sudden Unexplained Death ◽  
Unexplained Death

Sudden unexplained death in childhood (SUDC) is an understudied problem. Whole-exome sequence data from 124 “trios” (decedent child, living parents) was used to test for excessive de novo mutations (DNMs) in genes involved in cardiac arrhythmias, epilepsy, and other disorders. Among decedents, nonsynonymous DNMs were enriched in genes associated with cardiac and seizure disorders relative to controls (odds ratio = 9.76, P = 2.15 × 10−4). We also found evidence for overtransmission of loss-of-function (LoF) or previously reported pathogenic variants in these same genes from heterozygous carrier parents (11 of 14 transmitted, P = 0.03). We identified a total of 11 SUDC proband genotypes (7 de novo, 1 transmitted parental mosaic, 2 transmitted parental heterozygous, and 1 compound heterozygous) as pathogenic and likely contributory to death, a genetic finding in 8.9% of our cohort. Two genes had recurrent missense DNMs, RYR2 and CACNA1C. Both RYR2 mutations are pathogenic (P = 1.7 × 10−7) and were previously studied in mouse models. Both CACNA1C mutations lie within a 104-nt exon (P = 1.0 × 10−7) and result in slowed L-type calcium channel inactivation and lower current density. In total, six pathogenic DNMs can alter calcium-related regulation of cardiomyocyte and neuronal excitability at a submembrane junction, suggesting a pathway conferring susceptibility to sudden death. There was a trend for excess LoF mutations in LoF intolerant genes, where ≥1 nonhealthy sample in denovo-db has a similar variant (odds ratio = 6.73, P = 0.02); additional uncharacterized genetic causes of sudden death in children might be discovered with larger cohorts.

scholarly journals Whole-genome Sequencing Reveals De-novo Mutations Associated with Nonsyndromic Cleft Lip/Palate

2021 ◽  
Author(s):  
Waheed Awotoye ◽  
Peter A. Mossey ◽  
Jacqueline B. Hetmanski ◽  
Lord Jephthah Joojo Gowans ◽  
Mekonen A. Eshete ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Cleft Lip ◽  
De Novo ◽  
Association Studies ◽  
Whole Genome ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Pathogenic Variants ◽  
Cleft Lip Palate

Abstract The majority (85%) of nonsyndromic cleft lip with or without cleft palate (nsCL/P) cases occur sporadically, suggesting a role for de novo mutations (DNMs) in the etiology of nsCL/P. To identify high impact DNMs that contribute to the risk of nsCL/P, we conducted whole genome sequencing (WGS) analyses in 130 African case-parent trios (affected probands and unaffected parents). We identified 162 high confidence protein-altering DNMs that contribute to the risk of nsCL/P. These include novel loss-of-function DNMs in the ACTL6A, ARHGAP10, MINK1, TMEM5 and TTN genes; as well as missense variants in ACAN, DHRS3, DLX6, EPHB2, FKBP10, KMT2D, RECQL4, SEMA3C, SEMA4D, SHH, TP63, and TULP4. Experimental evidence showed that ACAN, DHRS3, DLX6, EPHB2, FKBP10, KMT2D, MINK1, RECQL4, SEMA3C, SEMA4D, SHH, TP63, and TTN genes contribute to facial development and mutations in these genes could contribute to CL/P. Association studies have identified TULP4 as a potential cleft candidate gene, while ARHGAP10 interacts with CTNNB1 to control WNT signaling. DLX6, EPHB2, SEMA3C and SEMA4D harbor novel damaging DNMs that may affect their role in neural crest migration and palatal development. This discovery of pathogenic DNMs also confirms the power of WGS analysis of trios in the discovery of potential pathogenic variants.

scholarly journals Recapitulation of the EEF1A2 D252H neurodevelopmental disorder-causing missense mutation in mice reveals a toxic gain of function

2020 ◽  
Vol 29 (10) ◽  
pp. 1592-1606 ◽  
Author(s):  
Faith C J Davies ◽  
Jilly E Hope ◽  
Fiona McLachlan ◽  
Grant F Marshall ◽  
Laura Kaminioti-Dumont ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Molecular Modelling ◽  
Neurodevelopmental Disorders ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Elongation Factor ◽  
Missense Mutations ◽  
Loss Of Function ◽  
De Novo Mutations ◽  
Gain Of Function

Abstract Heterozygous de novo mutations in EEF1A2, encoding the tissue-specific translation elongation factor eEF1A2, have been shown to cause neurodevelopmental disorders including often severe epilepsy and intellectual disability. The mutational profile is unusual; ~50 different missense mutations have been identified but no obvious loss of function mutations, though large heterozygous deletions are known to be compatible with life. A key question is whether the heterozygous missense mutations operate through haploinsufficiency or a gain of function mechanism, an important prerequisite for design of therapeutic strategies. In order both to address this question and to provide a novel model for neurodevelopmental disorders resulting from mutations in EEF1A2, we created a new mouse model of the D252H mutation. This mutation causes the eEF1A2 protein to be expressed at lower levels in brain but higher in muscle in the mice. We compared both heterozygous and homozygous D252H and null mutant mice using behavioural and motor phenotyping alongside molecular modelling and analysis of binding partners. Although the proteomic analysis pointed to a loss of function for the D252H mutant protein, the D252H homozygous mice were more severely affected than null homozygotes on the same genetic background. Mice that are heterozygous for the missense mutation show no behavioural abnormalities but do have sex-specific deficits in body mass and motor function. The phenotyping of our novel mouse lines, together with analysis of molecular modelling and interacting proteins, suggest that the D252H mutation results in a gain of function.

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