Publications by authors named "Mark Simcoe"

Purpose: We sought to explore whether sex imbalances are discernible in several autosomally inherited macular dystrophies.

Methods: We searched the electronic patient records of our large inherited retinal disease cohort, quantifying numbers of males and females with the more common (non-ABCA4) inherited macular dystrophies (associated with BEST1, EFEMP1, PROM1, PRPH2, RP1L1, and TIMP3). BEST1 cases were subdivided into typical autosomal dominant and recessive disease.

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Importance: Previous studies indicated that female sex might be a modifier in Stargardt disease, which is an ABCA4-associated retinopathy.

Objective: To investigate whether women are overrepresented among individuals with ABCA4-associated retinopathy who are carrying at least 1 mild allele or carrying nonmild alleles.

Data Sources: Literature data, data from 2 European centers, and a new study.

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Article Synopsis
  • This study focuses on understanding the genetic factors behind inherited retinal disease (IRD), a major cause of blindness, by analyzing a large cohort of patients in the UK who received molecular diagnoses from 2003 to 2020.
  • Researchers employed various genetic testing methods to identify disease-causing variants among patients, particularly examining variants in the most common IRD genes, such as ABCA4, USH2A, RPGR, PRPH2, and BEST1.
  • The findings revealed that 42.7% of families had variants in one of the five most common IRD genes, with specific insights into the prevalence and clustering of mutations in notable genes like USH2A and RPGR
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Purpose: Smoking may influence measured IOP through an effect on corneal biomechanics, but it is unclear whether this factor translates into an increased risk for glaucoma. This study aimed to examine the association of cigarette smoking with corneal biomechanical properties and glaucoma-related traits, and to probe potential causal effects using Mendelian randomization (MR).

Methods: Cross-sectional analyses within the UK Biobank (UKB) and Canadian Longitudinal Study on Aging (CLSA) cohorts.

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Purpose: To determine whether the ABCA4 retinopathy-associated variant p.Asn1868Ile (c.5603A>T) is associated with retinal structure or subclinical disease among the general population.

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Purpose: To identify genetic variants associated with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) in unrelated patients and to further understand the genetic and potentially causal relationships between PDS and associated risk factors.

Design: A 2-stage genome-wide association meta-analysis with replication and subsequent in silico analyses including Mendelian randomization.

Participants: A total of 574 cases with PG or PDS and 52 627 controls of European descent.

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Optical Coherence Tomography (OCT) enables non-invasive imaging of the retina and is used to diagnose and manage ophthalmic diseases including glaucoma. We present the first large-scale genome-wide association study of inner retinal morphology using phenotypes derived from OCT images of 31,434 UK Biobank participants. We identify 46 loci associated with thickness of the retinal nerve fibre layer or ganglion cell inner plexiform layer.

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Human eye color is highly heritable, but its genetic architecture is not yet fully understood. We report the results of the largest genome-wide association study for eye color to date, involving up to 192,986 European participants from 10 populations. We identify 124 independent associations arising from 61 discrete genomic regions, including 50 previously unidentified.

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Article Synopsis
  • * A large-scale study involving nearly 4,700 keratoconus cases and over 116,000 controls identified 36 genomic regions linked to the disease, highlighting issues with collagen integrity and cell differentiation as crucial factors.
  • * The findings reveal shared genetic mechanisms with other corneal diseases and suggest that the identified genetic variants account for 12.5% of keratoconus's genetic risk, paving the way for future diagnostic tests to assess susceptibility.
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Article Synopsis
  • Primary open-angle glaucoma (POAG) is a heritable eye condition leading to blindness and the study involved a large genetic analysis of over 34,000 patients and nearly 350,000 controls from different ethnic backgrounds.
  • Researchers identified 44 new genetic risk factors for POAG and confirmed 83 previously known ones, finding consistent impacts across various ancestries.
  • The study also suggests that certain genes could play significant roles in the disease's development, indicating potential new drug treatments targeting these genetic risk factors.
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Background/aims: Cascade screening has been used successfully in relatives of patients with inherited cancers and other genetic diseases to identify presymptomatic disease. This study was designed to examine if this approach would be successful in a high-risk group: first-degree relatives (FDR) of African-Caribbean glaucoma patients resident in London.

Methods: African-Caribbean patients (probands) with glaucoma from an inner London hospital setting in a deprived area were asked to disseminate personalised information to their FDR over the age of 30 and to arrange a free hospital-based screening.

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Purpose: The purpose of this study was to identify genetic variants on chromosome X associated with intraocular pressure (IOP) and determine if they possess any sex-specific effects.

Methods: Association analyses were performed across chromosome X using 102,407 participants from the UK Biobank. Replication and validation analyses were conducted in an additional 6599 participants from the EPIC-Norfolk cohort, and an independent 331,682 participants from the UK Biobank.

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SIX1/SIX6 polymorphism has been shown to be associated with glaucoma. Studies have also found that, in older adults, retinal nerve fibre layer (RNFL) thickness is significantly thinned with each copy of the risk allele in SIX1/SIX6. However, it is not known whether these genetic variants exert their effects in younger individuals.

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Corneal hysteresis and corneal resistance factor are parameters that reflect the dynamic biomechanical properties of the cornea and have been shown to be biomarkers of corneal disease. In this genome-wide association study of over 100 000 participants, we identified over 200 genetic loci, all but eight novel, significantly associated with either one or both of these traits. In addition to providing key insights into the genetic architecture underlying normal corneal function, these results identify many candidate loci in the study of corneal diseases that lead to severe visual impairment.

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Refractive errors, in particular myopia, are a leading cause of morbidity and disability worldwide. Genetic investigation can improve understanding of the molecular mechanisms that underlie abnormal eye development and impaired vision. We conducted a meta-analysis of genome-wide association studies (GWAS) that involved 542,934 European participants and identified 336 novel genetic loci associated with refractive error.

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Importance: Mechanisms behind pigmentary glaucoma, a form of early-onset glaucoma that may potentially lead to severe visual impairment or blindness, are poorly understood.

Objective: To calculate the single-nucleotide polymorphism (SNP) heritability of pigmentary glaucoma and identify genetic associations with the disease.

Design, Setting And Participants: This genome-wide association study included affected individuals from Germany and control participants from the United Kingdom.

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Article Synopsis
  • - The study focuses on using genome-wide association studies to analyze related traits for primary open-angle glaucoma (POAG), particularly looking at optic nerve head (ONH) parameters like cup area and disc area.
  • - It identifies new genetic variants linked to ONH traits that have significant implications for POAG, and these variants have been confirmed in independent Asian cohorts.
  • - However, the validation of these findings is complicated due to the diversity within POAG groups, suggesting that multi-trait analysis is an effective method for discovering new genetic factors.
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Article Synopsis
  • Primary open angle glaucoma (POAG) has a significant genetic component and shows varying prevalence among ethnic groups, being notably more common in black African populations.
  • A genome-wide association study involving Tanzanian, South African, and African American samples identified a confirmed association with the TXNRD2 gene and revealed a genetic risk score linked to 15 previously known POAG loci.
  • Additionally, a novel genetic locus associated with POAG was identified (EXOC4), but efforts to validate this finding in West African populations faced challenges due to genetic diversity, indicating the need for larger studies to better understand POAG in these groups.
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Glaucoma is the leading cause of irreversible blindness globally . Despite its gravity, the disease is frequently undiagnosed in the community . Raised intraocular pressure (IOP) is the most important risk factor for primary open-angle glaucoma (POAG).

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