Publications by authors named "Keren J Carss"

Article Synopsis
  • A study explored the effectiveness of using short-read and long-read genome sequencing to identify genetic causes of neurodevelopmental disorders (NDDs) in individuals who previously did not receive a genetic diagnosis.
  • The research involved 692 individuals, finding causal variants in 36% of affected individuals and uncertain variants in another 23%.
  • Long-read sequencing proved beneficial for resolving complex structural variants and improving the overall understanding of genetic contributions to NDDs.
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Human genetics research has discovered thousands of proteins associated with complex and rare diseases. Genome-wide association studies (GWAS) and studies of Mendelian disease have resulted in an increased understanding of the role of gene function and regulation in human conditions. Although the application of human genetics has been explored primarily as a method to identify potential drug targets and support their relevance to disease in humans, there is increasing interest in using genetic data to identify potential safety liabilities of modulating a given target.

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Background: Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndrome that predominantly affects women. Its pathophysiology remains unclear but connective tissue disorders (CTD) and other vasculopathies have been observed in many SCAD patients. A genetic component for SCAD is increasingly appreciated, although few genes have been robustly implicated.

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Importance: Sequencing studies have identified causal genetic variants for distinct subtypes of heart failure (HF) such as hypertrophic or dilated cardiomyopathy. However, the role of rare, high-impact variants in HF, for which ischemic heart disease is the leading cause, has not been systematically investigated.

Objective: To assess the contribution of rare variants to all-cause HF with and without reduced left ventricular ejection fraction.

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Background: Spontaneous coronary artery dissection (SCAD) occurs when an epicardial coronary artery is narrowed or occluded by an intramural hematoma. SCAD mainly affects women and is associated with pregnancy and systemic arteriopathies, particularly fibromuscular dysplasia. Variants in several genes, such as those causing connective tissue disorders, have been implicated; however, the genetic architecture is poorly understood.

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Purpose: Previous studies suggest that ceramide is a proapoptotic lipid as high levels of ceramides can lead to apoptosis of neuronal cells, including photoreceptors. However, no pathogenic variant in ceramide synthases has been identified in human patients and knockout of various ceramide synthases in mice has not led to photoreceptor degeneration.

Methods: Exome sequencing was used to identify candidate disease genes in patients with vision loss as confirmed by standard evaluation methods, including electroretinography (ERG) and optical coherence tomography.

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Background: Cys-loop receptors control neuronal excitability in the brain and their dysfunction results in numerous neurological disorders. Recently, six missense variants in GABRA2, a member of this family, have been associated with early infantile epileptic encephalopathy (EIEE). We identified a novel de novo missense variant in GABRA2 in a patient with EIEE and performed protein structural analysis of the seven variants.

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Article Synopsis
  • In families with multiple male children with intellectual disabilities (ID), a common assumption is that the cause is X-linked inheritance, leading to a focus on X-linked genes in genetic studies.
  • This research analyzed next-generation sequencing data from 274 individuals across 135 families, revealing that only 19% were genetically diagnosed, while 24% had uncertain variants and 12% had unique variants not shared within the family.
  • The findings indicate that while 43% of families had reportable variants, not all were X-linked, with 55% in X-linked genes and 38% in autosomal genes, suggesting that diverse genetic causes are present and caution is needed in assuming X linkage.
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The occurrence of non-epileptic hyperkinetic movements in the context of developmental epileptic encephalopathies is an increasingly recognized phenomenon. Identification of causative mutations provides an important insight into common pathogenic mechanisms that cause both seizures and abnormal motor control. We report bi-allelic loss-of-function CACNA1B variants in six children from three unrelated families whose affected members present with a complex and progressive neurological syndrome.

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The autosomal dominant progressive bifocal chorioretinal atrophy (PBCRA) disease locus has been mapped to chromosome 6q14-16.2 that overlaps the North Carolina macular dystrophy (NCMD) locus MCDR1. NCMD is a nonprogressive developmental macular dystrophy, in which variants upstream of PRDM13 have been implicated.

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Purpose: Using exome sequencing, the underlying variants in many persons with autosomal recessive diseases remain undetected. We explored autosomal recessive Stargardt disease (STGD1) as a model to identify the missing heritability.

Methods: Sequencing of ABCA4 was performed in 8 STGD1 cases with one variant and p.

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Background: Studies have shown that complex structural variants (cxSVs) contribute to human genomic variation and can cause Mendelian disease. We aimed to identify cxSVs relevant to Mendelian disease using short-read whole-genome sequencing (WGS), resolve the precise variant configuration and investigate possible mechanisms of cxSV formation.

Methods: We performed short-read WGS and analysis of breakpoint junctions to identify cxSVs in a cohort of 1324 undiagnosed rare disease patients.

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Background: Age-related macular degeneration (AMD) is a common sight threatening condition. However, there are a number of monogenic macular dystrophies that are clinically similar to AMD, which can potentially provide pathogenetic insights.

Methods: Three siblings from a non-consanguineous Greek-Cypriot family reported central visual disturbance and nyctalopia.

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Purpose: We describe the clinical features in two pedigrees with dominantly inherited retinopathy segregating the previously reported frameshifting mutation, c.836dupG (p.Ile280Asn*78) in the terminal exon of the RGR gene, and compare their haplotypes to that of the previously reported pedigree.

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Developmental and epileptic encephalopathies (DEEs) are severe neurodevelopmental disorders often beginning in infancy or early childhood that are characterized by intractable seizures, abundant epileptiform activity on EEG, and developmental impairment or regression. CACNA1E is highly expressed in the central nervous system and encodes the α-subunit of the voltage-gated Ca2.3 channel, which conducts high voltage-activated R-type calcium currents that initiate synaptic transmission.

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Purpose: Mutations in encoding ADP-ribosylation factor-like 2 binding protein, have recently been implicated as a cause of autosomal recessive retinitis pigmentosa (arRP), with three homozygous variants identified to date. In this study, we performed next-generation sequencing to reveal additional arRP cases associated with variants.

Methods: Whole-genome sequencing (WGS) or whole-exome sequencing (WES) was performed in 1,051 unrelated individuals recruited for the UK Inherited Retinal Disease Consortium and NIHR-BioResource Rare Diseases research studies.

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Article Synopsis
  • Next-generation sequencing has helped uncover genetic causes of various intellectual disabilities, revealing key mutations in the WASF1 gene in five individuals with moderate to profound disabilities, along with autism and seizures.* -
  • The identified mutations include three specific de novo truncating mutations in the WASF1 gene that likely disrupt its function related to actin polymerization.* -
  • Functional studies demonstrated that a specific mutation resulted in a truncated version of WASF1, leading to defects in actin remodeling in affected individuals, supporting the role of WASF1 mutations in this rare intellectual disability.*
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Background: The genetic cause of primary immunodeficiency disease (PID) carries prognostic information.

Objective: We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource-Rare Diseases cohort.

Methods: In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants.

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To date, over 150 disease-associated variants in CRB1 have been described, resulting in a range of retinal disease phenotypes including Leber congenital amaurosis and retinitis pigmentosa. Despite this, no genotype-phenotype correlations are currently recognised. We performed a retrospective review of electronic patient records to identify patients with macular dystrophy due to bi-allelic variants in CRB1.

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Background: Diagnostic use of gene panel next-generation sequencing (NGS) techniques is commonplace for individuals with inherited retinal dystrophies (IRDs), a highly genetically heterogeneous group of disorders. However, these techniques have often failed to capture the complete spectrum of genomic variation causing IRD, including CNVs. This study assessed the applicability of introducing CNV surveillance into first-tier diagnostic gene panel NGS services for IRD.

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Objective: To describe better the motor phenotype, molecular genetic features, and clinical course of -related disease.

Methods: We reviewed clinical information, video recordings, and neuroimaging of a newly identified cohort of 7 patients with de novo missense and splice site mutations, detected by next-generation sequencing techniques.

Results: Patients first presented in early childhood (median age of presentation 10 months, range 0-48 months), with a wide range of clinical symptoms ranging from severe motor and cognitive impairment with marked choreoathetosis, self-injurious behavior, and epileptic encephalopathy to a milder phenotype, featuring moderate developmental delay associated with complex stereotypies, mainly facial dyskinesia and mild epilepsy.

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Article Synopsis
  • Albinism is a group of disorders with reduced pigmentation, affecting the eyes and skin, and can sometimes present normally in hair and skin, specifically in ocular albinism linked to mutations in GPR143.
  • The study involved female carriers of GPR143 mutations, with advanced retinal imaging techniques used to explore retinal features and confirm atypical cases.
  • Findings revealed a novel mutation in one family, with signs of reduced foveal autofluorescence and a unique "tapetal-like" pattern at the macula in some patients, indicating retinal pigment changes in female carriers.
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