Phenotypic Heterogeneity of the Mitochondrial DNA Variant m.13513 G > A
The mitochondrial DNA (mtDNA) variant m.13513G > A is increasingly recognized as a cause of syndromic and nonsyndromic mitochondrial disorders (MIDs). This minireview aims a summarizing and discussing recent and previous findings about the phenotypic heterogeneity of this variant. A systematic literature review using the databases PubMed and Google Scholar by application of specific search terms was performed. As per the end of July 2021, at least 50 patients carrying the mtDNA variant m.13513G…
Genetic family studies and prospective evaluation for multisystem involvement are needed in LHON patients
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Clinical and genetic landscape of optic atrophy in 826 families: insights from 50 nuclear genes
Hereditary optic neuropathies (HON) are a group of diseases due to genetic defects either in mitochondria or in nuclear genomes. The increasing availability of genetic testing has expanded a broader genetic and phenotypic spectrum of HON than previously recognized. To provide systematic insight into the genetic and phenotypic landscape of HON attributed to 50 nuclear genes, we conducted genetic analysis on part of 4776 index patients with clinical diagnosis of HON following our previous study on…
Meta-analysis of treatment outcomes for patients with m.11778G>A MT-ND4 Leber Hereditary Optic Neuropathy
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). For the natural history and idebenone groups, we performed a systematic review of the literature and available clinical/regulatory reports. For the…
An Unusual Presentation of Leber Hereditary Optic Neuropathy-Plus Case Caused by a Novel DNAJC30 Variant
Leber hereditary optic neuropathy (LHON) is characterized by vision loss due to the degeneration of retinal ganglion cells. LHON-Plus refers to LHON with additional extraocular findings. Neurological conditions observed in LHON-Plus include seizures, encephalopathy, movement disorders, neuropathy, and myopathy. Herein, we present a case with atypical LHON-Plus caused by a novel DNAJC30 disease-causing gene variant. A 15-year-old boy presented with acute headache, and blurred and decreased vision…
Ganglion Cell Complex Thickness and Visual Function in Chronic Leber Hereditary Optic Neuropathy
CONCLUSIONS: The corrected GCC thickness showed correlation with visual function in chronic LHON subjects. The frequently occurring segmentation errors in OCT measurements related to chronic LHON can potentially be misleading in monitoring of disease progression and in evaluating the treatment effects. Precise measurements of GCC could serve as a sensitive tool to monitor structural changes in LHON. We therefore emphasize the importance of careful evaluation of the accuracy of OCT segmentation.
Recognizing Leber’s Hereditary Optic Neuropathy to avoid delayed diagnosis and misdiagnosis
Leber’s Hereditary Optic Neuropathy (LHON) is a maternally inherited optic nerve disease primarily caused by mutations in mitochondrial DNA (mtDNA). The peak of onset is typically between 15 and 30 years, but variability exists. Misdiagnosis, often as inflammatory optic neuritis, delays treatment, compounded by challenges in timely genetic diagnosis. Given the availability of a specific treatment for LHON, its early diagnosis is imperative to ensure therapeutic appropriateness. This work gives…
Preservation of Mitochondrial Function by SkQ1 in Skin Fibroblasts Derived from Patients with Leber’s Hereditary Optic Neuropathy Is Associated with the PINK1/PRKN-Mediated Mitophagy
Increased or altered mitochondrial ROS production in the retinal ganglion cells is regarded as the chief culprit of the disease-causing Leber’s hereditary optic neuropathy (LHON). SkQ1 is a rechargeable mitochondria-targeted antioxidant with high specificity and efficiency. SkQ1 has already been used to treat LHON patients, and a phase 2a randomized clinical trial of SkQ1 has demonstrated improvements in eyesight. However, the underlying mechanism of SkQ1 in LHON remains unclear. This study…
Retinal damage promotes mitochondrial transfer in the visual system of a mouse model of Leber hereditary optic neuropathy
Lenadogene nolparvovec is a gene therapy which has been developed to treat Leber hereditary optic neuropathy (LHON) caused by a point mutation in the mitochondrial NADH dehydrogenase 4 (ND4) gene. Clinical trials have demonstrated a significant improvement of visual acuity up to 5 years after treatment by lenadogene nolparvovec but, surprisingly, unilateral treatment resulted in bilateral improvement of vision. This contralateral effect – similarly observed with other gene therapy products in…
A transmitochondrial sodium gradient controls membrane potential in mammalian mitochondria
Eukaryotic cell function and survival rely on the use of a mitochondrial H^(+) electrochemical gradient (Δp), which is composed of an inner mitochondrial membrane (IMM) potential (ΔΨmt) and a pH gradient (ΔpH). So far, ΔΨmt has been assumed to be composed exclusively of H^(+). Here, using a rainbow of mitochondrial and nuclear genetic models, we have discovered that a Na^(+) gradient equates with the H^(+) gradient and controls half of ΔΨmt in coupled-respiring mammalian mitochondria. This…