Publications by authors named "Joseph A Marsh"

Genetically determined disorders are highly heterogenous in clinical presentation and underlying molecular mechanism. The evidence underpinning these conditions in the peer-reviewed literature requires robust critical evaluation for diagnostic use. Here, we present a structured curation process for Gene2Phenotype (G2P).

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Variant effect predictors (VEPs) are computational tools developed to assess the impacts of genetic mutations, often in terms of likely pathogenicity, employing diverse algorithms and training data. Here, we investigate the performance of 35 VEPs in the discrimination between pathogenic and putatively benign missense variants across 963 human protein-coding genes. We observe considerable gene-level heterogeneity as measured by the widely used area under the receiver operating characteristic curve (AUROC) metric.

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Advances in protein structure determination and modeling allow us to study the structural context of human genetic variants on an unprecedented scale. Here, we analyze millions of cancer-associated missense mutations based on their structural locations and predicted perturbative effects. By considering the collective properties of mutations at the level of individual proteins, we identify distinct patterns associated with tumor suppressors and oncogenes.

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Peptidyl arginine deiminase 6 (PADI6 or PAD6) is vital for early embryonic development in mice and humans, yet its function remains elusive. PADI6 is less conserved than other PADIs and it is currently unknown whether it has a catalytic function. Here we show that human PADI6 dimerises like hPADIs 2-4, however, does not bind Ca and is inactive in assays against standard PADI substrates.

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Many dominant genetic disorders result from protein-altering mutations, acting primarily through dominant-negative (DN), gain-of-function (GOF), and loss-of-function (LOF) mechanisms. Deciphering the mechanisms by which dominant diseases exert their effects is often experimentally challenging and resource intensive, but is essential for developing appropriate therapeutic approaches. Diseases that arise via a LOF mechanism are more amenable to be treated by conventional gene therapy, whereas DN and GOF mechanisms may require gene editing or targeting by small molecules.

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Background: Primary ciliary dyskinesia (PCD) is a genetic disorder affecting motile cilia. Most cases are inherited recessively, due to variants in >50 genes that result in abnormal or absent motile cilia. This leads to chronic upper and lower airway disease, subfertility, and laterality defects.

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  • Scientists found that a specific marker in melanoma (a type of skin cancer), called ALDH1A3, works with another protein called ACSS2 to help cancer cells use sugar (glucose) better and change their genes.
  • They discovered that acetaldehyde, which is a toxic substance, plays a role in this process and can help change gene activity in cancer cells.
  • In experiments with zebrafish that have melanoma, they showed that blocking ALDH1A3 can stop cancer cells from becoming resistant to treatment and may help doctors find new ways to fight the disease.
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  • UNC93B1 is a protein involved in signaling for Toll-like receptors, which are important for the immune response.
  • Mutations in UNC93B1 (I317M, G325C, L330R, R466S, and R525P) have been linked to conditions like systemic lupus erythematosus (SLE) and chilblain lupus (CBL), exhibiting both autosomal dominant and recessive inheritance patterns.
  • Different mutations impact the activity of TLR7 and TLR8 differently, suggesting that specific mutations in UNC93B1 lead to varying disease mechanisms for SLE and CBL.
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Nonsense and missense mutations in the transcription factor PAX6 cause a wide range of eye development defects, including aniridia, microphthalmia and coloboma. To understand how changes of PAX6:DNA binding cause these phenotypes, we combined saturation mutagenesis of the paired domain of PAX6 with a yeast one-hybrid (Y1H) assay in which expression of a PAX6-GAL4 fusion gene drives antibiotic resistance. We quantified binding of more than 2700 single amino-acid variants to two DNA sequence elements.

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Computational methods for assessing the likely impacts of mutations, known as variant effect predictors (VEPs), are widely used in the assessment and interpretation of human genetic variation, as well as in other applications like protein engineering. Many different VEPs have been released to date, and there is tremendous variability in their underlying algorithms and outputs, and in the ways in which the methodologies and predictions are shared. This leads to considerable challenges for end users in knowing which VEPs to use and how to use them.

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  • Tubulin is a key component of the cytoskeleton and has various isotypes in animals, but it's unclear how these isotypes influence microtubule structures in different cell types.
  • Research on 12 patients with primary ciliary dyskinesia and mouse models uncovered variants in the tubulin isotype that disrupted the formation of centrioles and cilia, impacting microtubule dynamics.
  • The study identified different variants causing distinct effects on tubulin interactions, allowing for the classification of patients into three types of ciliopathic diseases, highlighting the unique roles of specific tubulin isotypes in cellular functions.
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  • The translation elongation factor eEF1A2 is crucial for binding aminoacyl-tRNA to the ribosome, and since 2012, 21 harmful variants have been linked to severe neurodevelopmental disorders, including epilepsy and intellectual disabilities.
  • A recent study gathered 26 patients with EEF1A2 variants, revealing a milder clinical profile than previously reported, with higher walking and language skills and lower rates of intellectual disability and epilepsy.
  • The research identified 8 new EEF1A2 variants and suggests that severe and moderate phenotypes are linked to specific protein regions affecting GTP exchange, while milder variants may affect secondary functions, contributing to a broader understanding
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  • TLR7 plays a crucial role in detecting both viral and self-derived ssRNA, influencing the body's immune response.
  • Two novel mutations, F507S and L528I, in the TLR7 gene are linked to severe autoimmune conditions, with F507S occurring in a family and potentially affecting male subjects despite the gene being on the X chromosome.
  • These mutations highlight the importance of TLR7's dimerization in immune regulation and suggest that TLR7-related conditions may encompass a wider range of symptoms, including neurological issues.
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Abnormal increases in cell size are associated with senescence and cell cycle exit. The mechanisms by which overgrowth primes cells to withdraw from the cell cycle remain unknown. We address this question using CDK4/6 inhibitors, which arrest cells in G0/G1 and are licensed to treat advanced HR+/HER2- breast cancer.

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Machine-learning algorithm uses structure prediction to spot disease-causing mutations.

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The assessment of variant effect predictor (VEP) performance is fraught with biases introduced by benchmarking against clinical observations. In this study, building on our previous work, we use independently generated measurements of protein function from deep mutational scanning (DMS) experiments for 26 human proteins to benchmark 55 different VEPs, while introducing minimal data circularity. Many top-performing VEPs are unsupervised methods including EVE, DeepSequence and ESM-1v, a protein language model that ranked first overall.

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Protein complex assembly often occurs while subunits are being translated, resulting in complexes whose subunits were translated from the same mRNA in an allele-specific manner. It has thus been hypothesized that such cotranslational assembly may counter the assembly-mediated dominant-negative effect, whereby co-assembly of mutant and wild-type subunits "poisons" complex activity. Here, we show that cotranslationally assembling subunits are much less likely to be associated with autosomal dominant relative to recessive disorders, and that subunits with dominant-negative disease mutations are significantly depleted in cotranslational assembly compared to those associated with loss-of-function mutations.

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Many methodologically diverse computational methods have been applied to the growing challenge of predicting and interpreting the effects of protein variants. As many pathogenic mutations have a perturbing effect on protein stability or intermolecular interactions, one highly interpretable approach is to use protein structural information to model the physical impacts of variants and predict their likely effects on protein stability and interactions. Previous efforts have assessed the accuracy of stability predictors in reproducing thermodynamically accurate values and evaluated their ability to distinguish between known pathogenic and benign mutations.

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Recent discoveries have highlighted the prevalence of cotranslational assembly in proteomes, revealing a range of mechanisms that enables the assembly of protein complex subunits on the ribosome. Structural analyses have uncovered emergent properties that may inherently control whether a subunit undergoes cotranslational assembly. However, the evolutionary paths that have yielded such complexes over an extended timescale remain largely unclear.

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Purpose: STAT2 is both an effector and negative regulator of type I interferon (IFN-I) signalling. We describe the characterization of a novel homozygous missense STAT2 substitution in a patient with a type I interferonopathy.

Methods: Whole-genome sequencing (WGS) was used to identify the genetic basis of disease in a patient with features of enhanced IFN-I signalling.

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Neurodevelopmental disorder with visual defects and brain anomalies (NEDVIBA) is a recently described genetic condition caused by de novo missense HK1 variants. Phenotypic data is currently limited; only seven patients have been published to date. This descriptive case series of a further four patients with de novo missense HK1 variants, alongside integration of phenotypic data with the reported cases, aims to improve our understanding of the associated phenotype.

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