10 research outputs found

    Neurodevelopmental and other phenotypes recurrently associated with heterozygous BAZ2B loss-of-function variants

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    The bromodomain adjacent to zinc finger 2B (BAZ2B) gene encodes a chromatin remodeling protein that has been shown to perform a variety of regulatory functions. It has been proposed that loss of BAZ2B function is associated with neurodevelopmental phenotypes, and some recurrent structural birth defects and dysmorphic features have been documented among individuals carrying heterozygous loss-of-function BAZ2B variants. However, additional evidence is needed to confirm that these phenotypes are attributable to BAZ2B deficiency. Here, we report 10 unrelated individuals with heterozygous deletions, stop-gain, frameshift, missense, splice junction, indel, and start-loss variants affecting BAZ2B. These included a paternal intragenic deletion and a maternal frameshift variant that were inherited from mildly affected or asymptomatic parents. The analysis of molecular and clinical data from this cohort, and that of individuals previously reported, suggests that BAZ2B haploinsufficiency causes an autosomal dominant neurodevelopmental syndrome that is incompletely penetrant. The phenotypes most commonly seen in association with loss of BAZ2B function include developmental delay, intellectual disability, autism spectrum disorder, speech delay-with some affected individuals being non-verbal-behavioral abnormalities, seizures, vision-related issues, congenital heart defects, poor fetal growth, and an indistinct pattern of dysmorphic features in which epicanthal folds and small ears are particularly common.Genetics of disease, diagnosis and treatmen

    Relationship of the first step in protein synthesis to ppGpp: formation of A(5')ppp(5')Gpp.

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    Neurodevelopmental and other phenotypes recurrently associated with heterozygous BAZ2B loss-of-function variants

    No full text
    The bromodomain adjacent to zinc finger 2B (BAZ2B) gene encodes a chromatin remodeling protein that has been shown to perform a variety of regulatory functions. It has been proposed that loss of BAZ2B function is associated with neurodevelopmental phenotypes, and some recurrent structural birth defects and dysmorphic features have been documented among individuals carrying heterozygous loss-of-function BAZ2B variants. However, additional evidence is needed to confirm that these phenotypes are attributable to BAZ2B deficiency. Here, we report 10 unrelated individuals with heterozygous deletions, stop-gain, frameshift, missense, splice junction, indel, and start-loss variants affecting BAZ2B. These included a paternal intragenic deletion and a maternal frameshift variant that were inherited from mildly affected or asymptomatic parents. The analysis of molecular and clinical data from this cohort, and that of individuals previously reported, suggests that BAZ2B haploinsufficiency causes an autosomal dominant neurodevelopmental syndrome that is incompletely penetrant. The phenotypes most commonly seen in association with loss of BAZ2B function include developmental delay, intellectual disability, autism spectrum disorder, speech delay—with some affected individuals being non-verbal—behavioral abnormalities, seizures, vision-related issues, congenital heart defects, poor fetal growth, and an indistinct pattern of dysmorphic features in which epicanthal folds and small ears are particularly common

    Recurrent de novo missense variants across multiple histone H4 genes underlie a neurodevelopmental syndrome

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    Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes

    Recurrent de novo missense variants across multiple histone H4 genes underlie a neurodevelopmental syndrome

    No full text
    Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes.Genetics of disease, diagnosis and treatmen

    Recurrent de novo missense variants across multiple histone H4 genes underlie a neurodevelopmental syndrome

    No full text
    Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes

    De novo and inherited variants in ZNF292 underlie a neurodevelopmental disorder with features of autism spectrum disorder

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    Contains fulltext : 218267.pdf (Publisher’s version ) (Closed access)PURPOSE: Intellectual disability (ID) and autism spectrum disorder (ASD) are genetically heterogeneous neurodevelopmental disorders. We sought to delineate the clinical, molecular, and neuroimaging spectrum of a novel neurodevelopmental disorder caused by variants in the zinc finger protein 292 gene (ZNF292). METHODS: We ascertained a cohort of 28 families with ID due to putatively pathogenic ZNF292 variants that were identified via targeted and exome sequencing. Available data were analyzed to characterize the canonical phenotype and examine genotype-phenotype relationships. RESULTS: Probands presented with ID as well as a spectrum of neurodevelopmental features including ASD, among others. All ZNF292 variants were de novo, except in one family with dominant inheritance. ZNF292 encodes a highly conserved zinc finger protein that acts as a transcription factor and is highly expressed in the developing human brain supporting its critical role in neurodevelopment. CONCLUSION: De novo and dominantly inherited variants in ZNF292 are associated with a range of neurodevelopmental features including ID and ASD. The clinical spectrum is broad, and most individuals present with mild to moderate ID with or without other syndromic features. Our results suggest that variants in ZNF292 are likely a recurrent cause of a neurodevelopmental disorder manifesting as ID with or without ASD

    Recurrent de novo missense variants across multiple histone H4 genes underlie a neurodevelopmental syndrome

    Get PDF
    Chromatin is essentially an array of nucleosomes, each of which consists of the DNA double-stranded fiber wrapped around a histone octamer. This organization supports cellular processes such as DNA replication, DNA transcription, and DNA repair in all eukaryotes. Human histone H4 is encoded by fourteen canonical histone H4 genes, all differing at the nucleotide level but encoding an invariant protein. Here, we present a cohort of 29 subjects with de novo missense variants in six H4 genes (H4C3, H4C4, H4C5, H4C6, H4C9, and H4C11) identified by whole-exome sequencing and matchmaking. All individuals present with neurodevelopmental features of intellectual disability and motor and/or gross developmental delay, while non-neurological features are more variable. Ten amino acids are affected, six recurrently, and are all located within the H4 core or C-terminal tail. These variants cluster to specific regions of the core H4 globular domain, where protein-protein interactions occur with either other histone subunits or histone chaperones. Functional consequences of the identified variants were evaluated in zebrafish embryos, which displayed abnormal general development, defective head organs, and reduced body axis length, providing compelling evidence for the causality of the reported disorder(s). While multiple developmental syndromes have been linked to chromatin-associated factors, missense-bearing histone variants (e.g., H3 oncohistones) are only recently emerging as a major cause of pathogenicity. Our findings establish a broader involvement of H4 variants in developmental syndromes
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