Publications by authors named "Holly A Dubbs"

Pathogenic variants in the cyclin-dependent kinase-like 5 (CDKL5) gene are associated with CDKL5 deficiency disorder (CDD), a severe X-linked developmental and epileptic encephalopathy. Deletions affecting the 5' untranslated region (UTR) of CDKL5, which involve the noncoding exon 1 and/or alternatively spliced first exons (exons 1a-e), are uncommonly reported. We describe genetic and phenotypic characteristics for 15 individuals with CDKL5 partial gene deletions affecting the 5' UTR.

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Purpose: Genetic counselors (GCs) increasingly play key roles in advancing genomic medicine through innovative research. Here, we examine one large cohort of GCs' evolving contributions to the literature, with the goal of facilitating worldwide professional development for GCs through scholarly activities.

Methods: Publications were cataloged by members of the Section of Genetic Counseling (Section), established at the Children's Hospital of Philadelphia and the University of Pennsylvania in 2014, including publication year, journal, impact factor, and author position.

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Article Synopsis
  • Germline loss-of-function variants in the CTNNB1 gene are linked to neurodevelopmental disorders that include spastic diplegia and visual issues, making them a common genetic cause of cerebral palsy (CP).
  • A study analyzed genetic data from 404 individuals with pathogenic CTNNB1 variants, including newly detailed phenotypes for 52 cases, to explore how these variants relate to CP and other traits.
  • Findings showed that individuals with CTNNB1 variants exhibited similar clinical features, suggesting that CP is part of the neurodevelopmental disorder spectrum rather than a separate condition; two specific variants were found to disrupt WNT signaling processes.
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The vacuolar H+-ATPase is an enzymatic complex that functions in an ATP-dependent manner to pump protons across membranes and acidify organelles, thereby creating the proton/pH gradient required for membrane trafficking by several different types of transporters. We describe heterozygous point variants in ATP6V0C, encoding the c-subunit in the membrane bound integral domain of the vacuolar H+-ATPase, in 27 patients with neurodevelopmental abnormalities with or without epilepsy. Corpus callosum hypoplasia and cardiac abnormalities were also present in some patients.

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  • Semaphorins and plexins, important for brain development, include the PLXNA3 gene, which affects brain signaling and is linked to conditions like autism and intellectual disabilities in boys with specific genetic variants.
  • This study examined 14 boys with these hemizygous PLXNA3 variants, finding a range of issues such as autism, motor difficulties, and seizures, highlighting a connection between the gene variations and the severity of neurodevelopmental disorders.
  • The findings suggest a potential new X-linked intellectual disability syndrome tied to PLXNA3 variants and emphasize the need for more research on their impact in humans.
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Over the past decade, pathogenic variants in all members of the ASXL family of genes, ASXL1, ASXL2, and ASXL3, have been found to lead to clinically distinct but overlapping syndromes. Bohring-Opitz syndrome (BOPS) was first described as a clinical syndrome and later found to be associated with pathogenic variants in ASXL1. This syndrome is characterized by developmental delay, microcephaly, characteristic facies, hypotonia, and feeding difficulties.

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  • An amendment to the original paper has been released.
  • The amended paper includes important updates or corrections.
  • You can find the link to access this amendment at the top of the paper.
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Purpose: Sifrim-Hitz-Weiss syndrome (SIHIWES) is a recently described multisystemic neurodevelopmental disorder caused by de novo variants inCHD4. In this study, we investigated the clinical spectrum of the disorder, genotype-phenotype correlations, and the effect of different missense variants on CHD4 function.

Methods: We collected clinical and molecular data from 32 individuals with mostly de novo variants in CHD4, identified through next-generation sequencing.

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We previously reported a pathogenic de novo p.R342W mutation in the transcriptional corepressor CTBP1 in four independent patients with neurodevelopmental disabilities [1]. Here, we report the clinical phenotypes of seven additional individuals with the same recurrent de novo CTBP1 mutation.

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Importance: Although genetic testing is important for bringing precision medicine to children with epilepsy, it is unclear what genetic testing strategy is best in maximizing diagnostic yield.

Objectives: To evaluate the diagnostic yield of an exome-based gene panel for childhood epilepsy and discuss the value of follow-up testing.

Design, Setting, And Participants: A case series study was conducted on data from clinical genetic testing at Children's Hospital of Philadelphia was conducted from September 26, 2016, to January 8, 2018.

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Article Synopsis
  • Many genetic causes of developmental delays and intellectual disabilities (DD/ID) are rare and require large-scale DNA sequencing and data sharing for discovery.
  • A collaboration called GeneMatcher identified 13 individuals with protein-altering variants in the MED13 gene, with most mutations being de novo and linked to various developmental issues like autism and speech delays.
  • The study highlights potential pathogenic mutations affecting the MED13 protein's structure, contributing to our understanding of genetic factors involved in DD/ID and associating MED13 with similar disease genes in the CDK8-kinase module.
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Certain mutations can cause proteins to accumulate in neurons, leading to neurodegeneration. We recently showed, however, that upregulation of a wild-type protein, Ataxin1, caused by haploinsufficiency of its repressor, the RNA-binding protein Pumilio1 (PUM1), also causes neurodegeneration in mice. We therefore searched for human patients with PUM1 mutations.

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Background: X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder leading to the accumulation of very long chain fatty acids (VLCFA) due to a mutation in the ABCD1 gene. ABCD1 mutations lead to a variety of phenotypes, including cerebral X-ALD and adrenomyeloneuropathy (AMN) in affected males and 80% of carrier females. There is no definite genotype-phenotype correlation with intrafamilial variability.

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Background: Microtubules are dynamic polymers of / tubulin heterodimers that play a critical role in cerebral cortical development, by regulating neuronal migration, differentiation, and morphogenesis. Mutations in genes that encode either - or -tubulin or a spectrum of proteins involved in the regulation of microtubule dynamics lead to clinically devastating malformations of cortical development, including lissencephaly.

Methods: This is a single case report or a patient with lissencephaly, developmental delay, nystagmus, persistent hyperplastic primary vitreous, and infantile spasms, and undertook a neurogenetic workup.

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  • A case study of a 20-month-old girl highlights the discordance between her clinical symptoms (failure to thrive, developmental delay, patchy skin pigmentation) and her genetic findings, specifically a large chromosomal duplication.
  • Initial genetic testing showed a non-mosaic duplication on chromosome 15, which is usually linked to overgrowth, contrasting with her symptoms.
  • Further testing of skin biopsies revealed a complex genetic picture including a deletion on the X chromosome, indicating a variant Turner Syndrome and suggesting that her different cell lines arose from a mitotic event involving separate parental contributions.
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Through a multi-center collaboration study, we here report six individuals from five unrelated families, with mutations in KAT6A/MOZ detected by whole-exome sequencing. All five different de novo heterozygous truncating mutations were located in the C-terminal transactivation domain of KAT6A: NM_001099412.1: c.

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Here we describe three subjects with mosaic genome-wide paternal uniparental isodisomy (GWpUPD) each of whom presented initially with overgrowth, hemihyperplasia (HH), and hyperinsulinism (HI). Due to the severity of findings and the presence of additional features, SNP array testing was performed, which demonstrated mosaic GWpUPD. Comparing these individuals to 10 other live-born subjects reported in the literature, the predominant phenotype is that of pUPD11 and notable for a very high incidence of tumor development.

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