Publications by authors named "Patrick Yu-Wai Man"

Article Synopsis
  • The study investigates the long-term safety and efficacy of lenadogene nolparvovec, a gene therapy for Leber hereditary optic neuropathy (LHON) caused by the MT-ND4 gene variant, enrolling patients for up to 5 years after treatment.
  • Conducted between 2018 and 2022, the RESTORE trial followed patients who previously participated in two phase 3 studies, RESCUE and REVERSE, focusing on vision loss treatment; most participants were male with an average age of 35.9 years.
  • Results indicated that 94.7% of participants completed the initial studies, and 72.4% completed the 5-year follow-up, with key outcomes
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Our aim was to assess the visual outcomes of patients with Leber hereditary optic neuropathy (LHON) harboring the m.11778G>A MT-ND4 mutation who had no treatment (natural history) or received idebenone or lenadogene nolparvovec. Efficacy outcomes included clinically relevant recovery (CRR) from nadir and final best-corrected visual acuity (BCVA).

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Article Synopsis
  • Advances in ocular imaging have enhanced our understanding of mitochondrial retinopathies and optic neuropathies by analyzing the retina and optic nerve's structure and pathology.
  • * The article reviews key imaging characteristics, genetic, and clinical features to improve our understanding of these conditions' pathogenesis and clinical manifestations.
  • * It also examines the potential of these imaging techniques as biomarkers for treatment monitoring and decision-making, while discussing their limitations and future applications with emerging gene therapies.*
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The carbonic anhydrase 2 (Car2) gene encodes the primary isoenzyme responsible for aqueous humor (AH) production and plays a major role in the regulation of intraocular pressure (IOP). The CRISPR-Cas9 system, based on the ShH10 adenovirus-associated virus, can efficiently disrupt the Car2 gene in the ciliary body. With a single intravitreal injection, Car2 knockout can significantly and sustainably reduce IOP in both normal mice and glaucoma models by inhibiting AH production.

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Leber hereditary optic neuropathy (LHON) is a mitochondrial disease leading to rapid and severe bilateral vision loss. Idebenone has been shown to be effective in stabilizing and restoring vision in patients treated within 1 year of onset of vision loss. The open-label, international, multicenter, natural history-controlled LEROS study (ClinicalTrials.

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Inherited optic neuropathies affect around 1 in 10,000 people in England; in these conditions, vision is lost as retinal ganglion cells lose function or die (usually due to pathological variants in genes concerned with mitochondrial function). Emerging gene therapies for these conditions have emphasised the importance of early and expedient molecular diagnoses, particularly in the paediatric population. Here, we report our real-world clinical experience of such a population, exploring which children presented with the condition, how they were investigated and the time taken for a molecular diagnosis to be reached.

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Purpose: To describe the pattern of MRI changes in the pregeniculate visual pathway in Leber hereditary optic neuropathy (LHON).

Method: This retrospective observational study enrolled 60 patients with LHON between January 2015 and December 2021. The abnormal MRI features seen in the pregeniculate visual pathway were investigated, and then correlated with the causative mitochondrial DNA (mtDNA) mutation, the distribution of the MRI lesions and the duration of vision loss.

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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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Background: Leber Hereditary Optic Neuropathy (LHON) is the most common inherited mitochondrial disease characterized by bilateral, painless, subacute visual loss with a peak age of onset in the second to third decade. Historically, LHON was thought to be exclusively maternally inherited due to mutations in mitochondrial DNA (mtDNA); however, recent studies have identified an autosomal recessive form of LHON (arLHON) caused by point mutations in the nuclear gene, .

Case Presentations: In this study, we report the cases of three Eastern European individuals presenting with bilateral painless visual loss, one of whom was also exhibiting motor symptoms.

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Background: ATXN2 is the causative gene of spinocerebellar ataxia type 2 (SCA2) and has been implicated in glaucoma pathogenesis. Therefore, studying ocular changes in SCA2 could uncover clinically relevant changes.

Objective: The aim was to investigate optic disc and retinal architecture in SCA2.

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Purpose: To compare the diagnostic accuracy of the photopic negative response (PhNR) elicited by red-blue (RB) and white-white (WW) stimuli, for detection of retinal ganglion cell (RGC) dysfunction in a heterogeneous clinical cohort.

Methods: Adults referred for electrophysiological investigations were recruited consecutively for this single-centre, prospective, paired diagnostic accuracy study. PhNRs were recorded to red flashes (1.

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Adeno-associated virus serotype 2 (AAV2) is a viral vector that can be used to deliver therapeutic genes to diseased cells in the retina. One strategy for altering AAV2 vectors involves the mutation of phosphodegron residues, which are thought to be phosphorylated/ubiquitinated in the cytosol, facilitating degradation of the vector and the inhibition of transduction. As such, mutation of phosphodegron residues have been correlated with increased transduction of target cells, however, an assessment of the immunobiology of wild-type and phosphodegron mutant AAV2 vectors following intravitreal (IVT) delivery to immunocompetent animals is lacking in the current literature.

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Historically, distinct mitochondrial syndromes were recognised clinically by their ocular features. Due to their predilection for metabolically active tissue, mitochondrial diseases frequently involve the eye, resulting in a range of ophthalmic manifestations including progressive external ophthalmoplegia, retinopathy and optic neuropathy, as well as deficiencies of the retrochiasmal visual pathway. With the wider availability of genetic testing in clinical practice, it is now recognised that genotype-phenotype correlations in mitochondrial diseases can be imprecise: many classic syndromes can be associated with multiple genes and genetic variants, and the same genetic variant can have multiple clinical presentations, including subclinical ophthalmic manifestations in individuals who are otherwise asymptomatic.

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Inner mitochondrial membrane fusion and cristae shape depend on optic atrophy protein 1, OPA1. Mutations in lead to autosomal dominant optic atrophy (ADOA), an important cause of inherited blindness. The Guanosin Triphosphatase (GTPase) and GTPase effector domains (GEDs) of OPA1 are essential for mitochondrial fusion; yet, their specific roles remain elusive.

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Article Synopsis
  • * LHON results in rapid vision loss typically between ages 15-35, while DOA is a slower progressing condition that often appears in childhood, with distinct clinical presentations and a higher prevalence in males for LHON.
  • * Advances in genetic sequencing have identified more forms of mitochondrial optic neuropathies, with ongoing therapeutic research, including gene therapy, and idebenone being the only approved drug to treat a mitochondrial disorder.
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Article Synopsis
  • Early detection of visual impairment in young children is often overlooked due to their limited ability to cooperate with standard vision tests.
  • The Apollo Infant Sight (AIS) is a mobile health system that uses smartphone technology to analyze children's gazing behaviors and facial features to detect 16 different ophthalmic disorders.
  • In tests, AIS demonstrated strong performance in identifying visual impairment, achieving high accuracy both in clinical settings and for at-home use by untrained caregivers.
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Purpose: The purpose of this study was to determine the psychometric validity of the Visual Function Index (VF-14) for use by patients with Leber hereditary optic neuropathy (LHON).

Methods: Rasch analysis was conducted in two stages using data for 196 individuals (74.5% male) carrying one of the three primary LHON mutations and affected by vision loss.

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Article Synopsis
  • The study aimed to explore the clinical and genetic aspects of childhood-onset Leber hereditary optic neuropathy (LHON) to understand how it affects visual outcomes.
  • It included a retrospective analysis of 68 patients under 12 years old from Italy and the UK, using various ophthalmologic evaluations to assess visual loss.
  • Results indicated that children who experience visual loss before age 9 have better visual outcomes compared to those affected later, suggesting that earlier onset might correlate with a milder form of the disease.
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Leber Hereditary Optic Neuropathy (LHON) is an inherited mitochondrial retinal disease that causes the degeneration of retinal ganglion cells and leads to drastic loss of visual function. In the last decades, there has been a growing interest in using Magnetic Resonance Imaging (MRI) to better understand mechanisms of LHON beyond the retina. This is partially due to the emergence of gene-therapies for retinal diseases, and the accompanying expanded need for reliably quantifying and monitoring visual processing and treatment efficiency in patient populations.

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Purpose: To evaluate the safety profile of lenadogene nolparvovec (Lumevoq) in patients with Leber hereditary optic neuropathy.

Design: Pooled analysis of safety data from 5 clinical studies.

Methods: A total of 189 patients received single unilateral or bilateral intravitreal injections of a recombinant adeno-associated virus 2 (rAAV2/2) vector encoding the human wild-type ND4 gene.

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Article Synopsis
  • Lenadogene nolparvovec is a novel gene therapy showing significant promise for improving visual acuity in patients with Leber hereditary optic neuropathy (LHON) who have the m.11778G>A ND4 mutation, with updated data increasing the number of treated patients from 76 to 174.
  • The therapy was compared against an external control group and resulted in a mean improvement in visual acuity of -0.30 logMAR, which is equivalent to +15 ETDRS letters, showing clinically relevant and sustained benefits over a follow-up period of up to 3.9 years.
  • Results indicate that most treated eyes retained measurable vision compared to less than half of those in the natural history group, and a
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Article Synopsis
  • The review analyzes current treatments for Leber hereditary optic neuropathy (LHON), focusing on both mutation-specific and mutation-independent approaches.
  • Mutation-specific therapies aim to correct genetic mutations or replace faulty mitochondrial DNA, with recent trials showing positive results for treatments targeting the m.11778G > A mutation when initiated soon after symptom onset.
  • Mutation-independent therapies, like Idebenone, help enhance mitochondrial function and neural cell survival, and ongoing pre-clinical gene therapies may also offer future options for LHON patients.
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