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Background: MCDs, or mitochondrial disorders, are a major contributor to morbidity and mortality. There are few studies on the prevalence of gene mutations in pediatric MCD patients in Egypt. The objective of the current study was to determine the frequencies of the most prevalent mtDNA mutations in a group of Egyptian children with classical mitochondrial disorders. Methods: Over two years, 140 pediatric patients clinically suspected of having classical mitochondrial disorders and 50 controls were examined for the most prevalent mtDNA mutations at Cairo University Children's Hospital. Polymerase Chain Reaction/Restriction Fragment Length Polymorphism analyses were used to screen for the 17 most common mtDNA mutations (G3460A, G11778A, T14484C, T3271C, G13513A, A3243G, A8344G, G8363A, T9176C, T8993C/G, A8344G, T8356C, G8363A, C3303T, A3260G, A4300G, and C9997T) based on the suspected syndrome. To validate the abnormal patterns, direct sequencing was carried out. Results: Of the 114 children evaluated, 54 were female and 60 were male, with a median age (range) of 3.5 years (7 months–16 years). 77 out of 114 (67.5%) patients were born into consanguineous marriages. Merely 1.8% of mtDNA point mutations were detected; of those with Leber's hereditary optic neuropathy, only two had the homoplasmic pathogenic variant T14484C of MTND6 verified. Conclusions: Screening for the most prevalent mtDNA mutations could be used as preliminary noninvasive testing for such syndromes. The low positive incidence raises the possibility that these mtDNA point mutations are not unique to pediatric patients in Egypt. Given Egypt's high percentage of consanguineous marriage, the molecular pathogenesis of such disorders is suspected to be of nuclear genetic origin. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON), a maternally inherited ocular disease, is predominantly caused by mitochondrial DNA (mtDNA) mutations. Mitochondrial tRNA variants are hypothesized to amplify the pathogenic impact of three primary mutations. However, the exact mechanisms remained unclear. In the present study, the synergistic effect of the tRNAGlu 14693A > G and ND6 14484T > C mutations in three Chinese families affected by LHON is investigated. The m.14693A > G mutation nearly abolishes the pseudouridinylation at position 55 of tRNAGlu, leading to structural abnormalities, decreased stability, aberrant mitochondrial protein synthesis, and increased autophagy. In contrast, the ND6 14484T > C mutation predominantly impairs complex I function, resulting in heightened apoptosis and virtually no induction of mitochondrial autophagy compared to control cell lines. The presence of dual mutations in the same cell lines exhibited a coexistence of both upregulated cellular stress responses to mitochondrial damage, indicating a scenario of autophagy and mutation dysregulation within these dual‐mutant cell lines. The data proposes a novel hypothesis that mitochondrial tRNA gene mutations generally lead to increased mitochondrial autophagy, while mutations in genes encoding mitochondrial proteins typically induce apoptosis, shedding light on the intricate interplay between different genetic factors in the manifestation of LHON. [ABSTRACT FROM AUTHOR]

To compare the outcomes of rAAV2-ND4 injection in treated versus fellow eyes with Leber's hereditary optic neuropathy (LHON). The protocol was pre-registered on PROSPERO (CRD42023441669). PubMed, Ovid MEDLINE, Cochrane CENTRAL, Google Scholar, Embase, CrossRef, OpenAlex, and Web of Science were reviewed from 1990–2023. Our analysis included 358 eyes of 307 patients. Of them, 256 (83%) patients received unilateral injections while 51 (17%) received bilateral injections. The mean age was 32 years. Baseline visual acuity (VA) of unilaterally injected eyes was 1.62. At 1 year, it was 1.6 compared to 1.4 (p = 0.002) in noninjected eyes. Baseline VA of bilaterally injected eyes was 1.6 and postoperatively at 1.5 years, it became 1.3 (p = 0.003). rAAV2/2-ND4 intravitreal injections showed no major differences in terms of improving visual acuity between treated and untreated eyes of the same patient. However, larger prospective RCTs, especially concerning OCT parameters, and visual field, are recommended to provide a better understanding and comparison. [ABSTRACT FROM AUTHOR]

We report the case of a 24-year-old previously healthy man who presented with an unusual combination of myelin oligodendrocyte glycoprotein antibody-associated optic neuritis (MOG-ON) and Leber’s hereditary optic neuropathy (LHON). Initially experiencing two episodes of painless visual acuity reduction, the patient responded well to glucocorticoid therapy, coinciding with an MOG antibody titre of 1:32. However, a subsequent third episode of painless vision loss did not improve with continued glucocorticoid treatment. Further diagnostic workup revealed a mitochondrial DNA mutation (11778 G>A), confirming the diagnosis of LHON. This unique presentation highlights the necessity of considering multiple aetiologies in cases of optic neuropathy where the cause is not immediately apparent, especially when the response to standard treatments is inconsistent. Our findings suggest that dual pathologies may coexist and should be considered in unexplained cases of optic neuropathy to facilitate appropriate clinical management. [ABSTRACT FROM AUTHOR]

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 an updated guidance about LHON differential diagnosis to clinicians dealing also with multiple sclerosi and neuromyelitis optica spectrtum disorders-related optic neuritis. LHON diagnosis relies on clinical signs and paraclinical evaluations. Differential diagnosis in the acute phase primarily involves distinguishing inflammatory optic neuropathies, considering clinical clues such as ocular pain, fundus appearance and visual recovery. Imaging analysis obtained with Optical Coherence Tomography (OCT) assists clinicians in early recognition of LHON and help avoiding misdiagnosis. Genetic testing for the three most common LHON mutations is recommended initially, followed by comprehensive mtDNA sequencing if suspicion persists despite negative results. We present and discuss crucial strategies for accurate diagnosis and management of LHON cases. [ABSTRACT FROM AUTHOR]

Hereditary optic neuropathies (HONs) are a class of genetic disorders that may lead to vision loss due to either acute or progressive injury to the optic nerve. Although HONs may commonly manifest as isolated optic atrophy, these disorders can also have a variety of characteristic clinical features and time courses that may narrow the differential diagnosis. While the two most prevalent HONs are Leber Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), the phenotypic spectrum of these conditions, as well as genetic landscape of less common optic neuropathies, have been better characterized through advances in molecular diagnostic testing. Treatment targeting various pathogenic mechanisms has been investigated, although studies of clinical applicability remain nascent. Present management largely remains supportive. In this review, we discuss the clinical features, molecular diagnosis, current treatment, and future directions for HONs. [ABSTRACT FROM AUTHOR]

Purpose: To objectively assess visual function in Leber's Hereditary Optic Neuropathy (LHON) patients; this study evaluated pre- and post-idebenone treatment changes in primary visual cortical (V1) responses using functional magnetic resonance imaging (fMRI), given the challenges in subjective testing due to central retinal ganglion cell damage. Study design: A descriptive study involving four confirmed LHON patients. Methods: Four patients received 900 mg/day of oral idebenone for 24 weeks. Baseline and post-treatment visual acuity, visual fields, and BOLD fMRI responses while passively viewed drifting contrast pattern visual stimuli were compared with self-reported symptoms. Results: Post-idebenone, one patient showed positive trends across subjective tests, reported symptoms, and fMRI. Two patients had stable symptoms and fMRI responses; one improved on subjective tests, and another worsened slightly. Another patient improved in visual field tests despite worsening symptoms and fMRI trends. Conclusion: fMRI may offer a valuable objective measure of visual functions in LHON and appears to be more relevant in assessing symptoms. Further research with more participants is needed to ascertain fMRI's role in developing objective visual assessments and treatment evaluation. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by visual loss, and rarely associated with extraocular manifestations including multiple sclerosis‐like lesions. The association of LHON and neuromyelitis optica spectrum disorders has rarely been reported. Here is reported a case of glial fibrillary acidic protein astrocytopathy presenting with area postrema syndrome in a patient with previously diagnosed recessive LHON due to mutations in the nuclear gene DNAJC30. This case emphasizes the necessity of extensive investigations for other treatable conditions in patients with LHON and otherwise unexplained extraocular involvement and the possibility that also visual symptoms can respond to immune therapy. [ABSTRACT FROM AUTHOR]

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 aimed to assess the effects and molecular mechanism of SkQ1 in the preservation of mitochondrial function using skin fibroblasts derived from LHON patients. Our study found that SkQ1 could reduce ROS production and stabilize the mitochondrial membrane. Mechanistically, through network pharmacology and molecular docking, we identified the key targets of SkQ1 as SOD2 and PINK1, which play crucial roles in redox and mitophagy. SkQ1 interacted with PINK1 and downregulated its expression to balance mitochondrial homeostasis. Collectively, the findings of our study reveal that by regulating PINK1/PRKN-mediated mitophagy, SkQ1 preserves mitochondrial function in LHON fibroblasts. The data indicate that SkQ1 may be a novel therapeutic intervention to prevent the progression of LHON. [ABSTRACT FROM AUTHOR]

Abstract Background MCDs, or mitochondrial disorders, are a major contributor to morbidity and mortality. There are few studies on the prevalence of gene mutations in pediatric MCD patients in Egypt. The objective of the current study was to determine the frequencies of the most prevalent mtDNA mutations in a group of Egyptian children with classical mitochondrial disorders. Methods Over two years, 140 pediatric patients clinically suspected of having classical mitochondrial disorders and 50 controls were examined for the most prevalent mtDNA mutations at Cairo University Children’s Hospital. Polymerase Chain Reaction/Restriction Fragment Length Polymorphism analyses were used to screen for the 17 most common mtDNA mutations (G3460A, G11778A, T14484C, T3271C, G13513A, A3243G, A8344G, G8363A, T9176C, T8993C/G, A8344G, T8356C, G8363A, C3303T, A3260G, A4300G, and C9997T) based on the suspected syndrome. To validate the abnormal patterns, direct sequencing was carried out. Results Of the 114 children evaluated, 54 were female and 60 were male, with a median age (range) of 3.5 years (7 months–16 years). 77 out of 114 (67.5%) patients were born into consanguineous marriages. Merely 1.8% of mtDNA point mutations were detected; of those with Leber’s hereditary optic neuropathy, only two had the homoplasmic pathogenic variant T14484C of MTND6 verified. Conclusions Screening for the most prevalent mtDNA mutations could be used as preliminary noninvasive testing for such syndromes. The low positive incidence raises the possibility that these mtDNA point mutations are not unique to pediatric patients in Egypt. Given Egypt’s high percentage of consanguineous marriage, the molecular pathogenesis of such disorders is suspected to be of nuclear genetic origin.

Leber’s hereditary optic neuropathy (LHON) causes subacute visual loss, and, in the acute phase, the optic disc shows hyperemia, peripapillary telangiectasia, and swelling of the retinal nerve fiber layer (RNFL). Rarely, retinal hemorrhage may be present. In this study, we investigated LHON cases with retinal hemorrhage in the acute phase. Among 82 cases (164 eyes) of LHON who visited the Inoue Eye Hospital, retinal hemorrhage was observed in 5 cases (5 eyes). The age at onset was 36 (27–46) years, with 4 male cases. Mitochondrial DNA analysis revealed the presence of the m.11778G > A variant in four patients and the m.14484T > C variant in one patient. There was no medical history and no excessive smoking or alcohol consumption in any of the cases. In all cases, retinal hemorrhages were observed in the RNFL, accompanying the characteristic optic disc findings of LHON. Fluorescein angiography performed in three cases showed no leakage from the optic disc or blood vessels. While rare, the presence of retinal hemorrhage along the RNFL during the acute phase of LHON should be recognized, as it may warrant consideration of alternative diagnoses. [ABSTRACT FROM AUTHOR]

Abstract Leber's hereditary optic neuropathy (LHON), a maternally inherited ocular disease, is predominantly caused by mitochondrial DNA (mtDNA) mutations. Mitochondrial tRNA variants are hypothesized to amplify the pathogenic impact of three primary mutations. However, the exact mechanisms remained unclear. In the present study, the synergistic effect of the tRNAGlu 14693A > G and ND6 14484T > C mutations in three Chinese families affected by LHON is investigated. The m.14693A > G mutation nearly abolishes the pseudouridinylation at position 55 of tRNAGlu, leading to structural abnormalities, decreased stability, aberrant mitochondrial protein synthesis, and increased autophagy. In contrast, the ND6 14484T > C mutation predominantly impairs complex I function, resulting in heightened apoptosis and virtually no induction of mitochondrial autophagy compared to control cell lines. The presence of dual mutations in the same cell lines exhibited a coexistence of both upregulated cellular stress responses to mitochondrial damage, indicating a scenario of autophagy and mutation dysregulation within these dual‐mutant cell lines. The data proposes a novel hypothesis that mitochondrial tRNA gene mutations generally lead to increased mitochondrial autophagy, while mutations in genes encoding mitochondrial proteins typically induce apoptosis, shedding light on the intricate interplay between different genetic factors in the manifestation of LHON.

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 an updated guidance about LHON differential diagnosis to clinicians dealing also with multiple sclerosi and neuromyelitis optica spectrtum disorders-related optic neuritis. LHON diagnosis relies on clinical signs and paraclinical evaluations. Differential diagnosis in the acute phase primarily involves distinguishing inflammatory optic neuropathies, considering clinical clues such as ocular pain, fundus appearance and visual recovery. Imaging analysis obtained with Optical Coherence Tomography (OCT) assists clinicians in early recognition of LHON and help avoiding misdiagnosis. Genetic testing for the three most common LHON mutations is recommended initially, followed by comprehensive mtDNA sequencing if suspicion persists despite negative results. We present and discuss crucial strategies for accurate diagnosis and management of LHON cases.

Abstract In order to explore the spectrum of mitochondrial DNA (mtDNA) mutations in Korean patients with Leber's hereditary optic neuropathy (LHON), we investigated the spectrum of mtDNA mutations in 145 Korean probands confirmed with the diagnosis of LHON. Total genomic DNA was isolated from the peripheral blood leukocytes of the patients with suspected LHON, and mtDNA mutations were identified by direct sequencing. Analysis of mtDNA mutations revealed seven primary LHON mutations including the nucleotide positions (nps) 11778A (101 probands, 69.2%), 14484C (31 probands, 21.2%), 3460A (5 probands, 3.4%), and G3635A, G3733A, C4171A, and G13051A mutations in one proband each. In addition, two provisional mtDNA mutations at nps T3472C, and G13259A were each found in one proband, respectively. Another provisional mtDNA mutation at np T3394C was found in two probands. In conclusion, the spectrum of mtDNA mutations in Korean patients with LHON may differ from other ethnicities, which is characterized by high prevalence of 11778A and 14484C mutations, and a low prevalence of the 3460A mutation.

Purpose: Reports of atypical cases have increased awareness that Leber's hereditary optic neuropathy (LHON) is not solely a disease of young men. Here, we present a case of a 70-year-old woman who presented with bilateral sequential loss of vision, and, after several diagnostic dilemmas, was ultimately found to have LHON. Observations: Our patient presented with a one-month history of progressive central vision loss in the right eye. Her visual acuities were 20/200-1 and 20/25-2. She had no afferent pupillary defect and intraocular pressures were normal. Fundus examination revealed cup-to-disc ratios of 0.9 and 0.7 with an inferior notch on the right. Visual fields showed superior arcuate and cecocentral depressions on the right and an inferior nasal step on the left. Ocular coherence tomography showed bilateral, superior and inferior retinal nerve fiber layer thinning. She was diagnosed with normal-tension glaucoma. Laboratory studies and neuroimaging were unremarkable. One month later, she presented with new central vision loss in the left eye. Ocular coherence tomography revealed new, mild optic nerve swelling in the left eye. Due to concern for an acute-on-chronic process, she was hospitalized and treated with intravenous steroids and later plasmapheresis with modest improvement. An extensive laboratory evaluation, lumbar puncture, temporal artery biopsy, and PET CT were normal. Mitochondrial genetic testing was ordered. After a six-week delay, the results revealed a pathogenic variant at mitochondrial position 11778, consistent with a diagnosis of LHON. She began treatment with idebenone. At the most recent visit, her vision had improved to 20/40 and 20/30. Conclusions and importance: LHON is typically not part of the initial differential diagnosis of an optic neuropathy in patients outside the typical demographic. As genetic testing has become more widely available, clinicians should consider including LHON in their differential diagnosis of any optic neuropathy, especially if other, more common causes have been ruled out.

Optic neuropathies are characterized by the degeneration of the optic nerves and represent a considerable individual and societal burden. Notably, Leber's hereditary optic neuropathy (LHON) is a devastating vision disease caused by mitochondrial gene mutations that hinder oxidative phosphorylation and increase oxidative stress, leading to the loss of retinal ganglion neurons and axons. Loss of vision is rapid and severe, predominantly in young adults. Penetrance is incomplete, and the time of onset is unpredictable. Recent findings revealed that the incidence of genetic LHON susceptibility is around 1 in 1000, much higher than believed till now. Environmental factors are critical in LHON triggering or severity. Families at risk have a very strong demand for how to prevent the onset or limit the severity of the disease. Here, we review recent knowledge of the extrinsic determinants of LHON expression, including lifestyle, dietary supplements, common chemicals, and drugs. [ABSTRACT FROM AUTHOR]

Purpose: To describe a case with Leber's hereditary optic neuropathy (LHON) like optic atrophy in the presence of MT-ATP6 gene variant m.8969G > A. Observations: A 20-year-old patient with a history of mild developmental delay, mild cognitive impairment, and positional tremor presented with subacute painless visual loss over a few weeks. Mitochondrial genome sequencing revealed a variant in MT-ATP6, m.8969G > A (p.Ser148Asn). This variant was previously reported in association with mitochondrial myopathy, lactic acidosis, and sideroblastic anemia (MLASA) and with nephropathy, followed by brain atrophy, muscle weakness and arrhythmias, but not with optic atrophy. Conclusions and importance: Rare variants in MT-ATP6 can also cause LHON like optic atrophy. It is important to perform further genetic analysis of mitochondrial DNA in genetically unsolved cases suspected of Leber's hereditary optic neuropathy to confirm the clinical diagnosis.

Lebers Hereditary Optic Neuropathy (LHON) is the most common primary mitochondrial DNA disorder. It is characterized by bilateral severe central subacute vision loss due to specific loss of Retinal Ganglion Cells and their axons. Historically, treatment options have been quite limited, but ongoing clinical trials show promise, with significant advances being made in the testing of free radical scavengers and gene therapy. In this review, we summarize management strategies and rational of treatment based on current insights from molecular research. This includes preventative recommendations for unaffected genetic carriers, current medical and supportive treatments for those affected, and emerging evidence for future potential therapeutics.

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 aimed to assess the effects and molecular mechanism of SkQ1 in the preservation of mitochondrial function using skin fibroblasts derived from LHON patients. Our study found that SkQ1 could reduce ROS production and stabilize the mitochondrial membrane. Mechanistically, through network pharmacology and molecular docking, we identified the key targets of SkQ1 as SOD2 and PINK1, which play crucial roles in redox and mitophagy. SkQ1 interacted with PINK1 and downregulated its expression to balance mitochondrial homeostasis. Collectively, the findings of our study reveal that by regulating PINK1/PRKN-mediated mitophagy, SkQ1 preserves mitochondrial function in LHON fibroblasts. The data indicate that SkQ1 may be a novel therapeutic intervention to prevent the progression of LHON.

Leber's hereditary optic neuropathy (LHON) is one of the hereditary optic neuropathies and is principally caused by three frequent mitochondria deoxyribonucleic acid (DNA) pathogenic variants (m.11778 G>A, m.3460 G>A, and m.14484T>C). These pathogenic variants account for 90% of LHON cases, with rare pathogenic variants accounting for the remaining cases. We report the first Japanese case of LHON with the m.13051 G>A pathogenic variant, which is a rare primary pathogenic variant of LHON. A 24-year-old woman developed subacute visual loss in both eyes over several months. The best corrected visual acuity (BCVA) was 6/120 in her right eye (OD) and 6/7.5 in her left eye (OS). A relative afferent pupillary defect was not detected. Humphrey visual field testing revealed a central scotoma OD and a temporal paracentral scotoma OS. Fundus examination showed the presence of a pale optic disc OD and optic disc swelling with peripapillary microangiopathy OS. Orbital magnetic resonance imaging showed no abnormal findings. As the mitochondrial DNA gene testing demonstrated the m.13051 G>A pathogenic variant, the patient was diagnosed with LHON. Subsequently, her BCVA worsened to 6/600 in each eye, followed by a nearly plateau-like progression thereafter. This mutation has been primarily reported in Europe but has not yet been confirmed in the Asian region. This case also indicates the importance of examining the whole mitochondrial DNA gene for pathogenic variants in cases where one of the three major pathogenic variants has not been not detected. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease with central vision loss as the main symptom. It is one of the diseases that cause vision loss and optic atrophy in young and middle-aged people. The mutations of these three primary mitochondrial mutations, m.11778G>A, m.14484T>C, and m.3460G>A, are the main molecular basis, but their pathogenesis is also affected by nuclear genes, mitochondrial genetic background, and environmental factors. This article summarizes the research progress on molecular pathogenesis, clinical symptoms, and treatment of LHON in recent years, aiming to summarize the genetic pathogenesis and clinical treatment points of LHON. [ABSTRACT FROM AUTHOR]

Purpose: Peripapillary hyperreflective ovoid mass-like structures (PHOMS) represent an optical coherence tomography (OCT) finding that has been characterized in different forms of pseudopapilledema. The aim of this study was to investigate the prevalence of PHOMS in patients affected by acute LHON using structural OCT, and to provide a detailed description of these findings. Methods: Patients with a clinical and molecularly confirmed diagnosis of acute LHON (visual loss having occurred less than 6 months) were enrolled from the neuro-ophthalmology clinic at San Raffaele Scientific Institute. Patients had a complete ophthalmologic evaluation, including imaging with structural OCT. Results: Our analysis included 16 patients (21 eyes—8 males and 8 females) with acute LHON. Structural OCT exhibited PHOMS in 12 eyes from 9 patients with a prevalence rate of 57.1%. In a subsequent topographical assessment in the peripapillary area, the most common location of PHOMS was the temporal region (12 out of 12 eyes), while the nasal region was affected in 2 eyes (16.7%). Considering the 12 eyes with PHOMS, mean ± SD temporal peripapillary RNFL thickness was 87.5 ± 28.4 microns. The temporal peripapillary RNFL thickness was significantly lower in eyes without PHOMS (63.7 ± 32.2 microns; P = 0.40). At the 12-month follow-up visit, PHOMS disappeared in 10 out of 12 eyes. Conclusions: Acute LHON eyes have PHOMS which are mainly confined to the temporal peripapillary sector. PHOMS may represent swelled retinal fibers that have herniated or are in stasis. [ABSTRACT FROM AUTHOR]

This article reviews the clinical data of a patient with Leber's hereditary optic neuropathy, and summarizes Traditional Chinese Medicine (TCM) external treatment and related nursing measures. Under the guidance of TCM theory and syndrome differentiation, external treatments such as auricular acupuncture, plum-blossom acupuncture, and Chinese medicine iontophoresis were carried out to relieve visual impairment of the patient. Routine nursing interventions including nutrition support and emotion care were implemented for better compliance during the treamtent. (本文总结1例Leber家族遗传性视神经病患者中医外治护理体会。基于中医理论指导辨证施护, 采用耳穴贴压、梅花针、中药离子导入中医外治, 同时配合饮食护理、情志护理等常规护理干预, 有助于提高患者治疗依从性, 缓解视力障碍。)

Abstract Background Leber’s hereditary optic neuropathy (LHON) is a maternally inherited eye disease due to mutations in mitochondrial DNA. However, there is no effective treatment for this disease. LHON-linked ND6 14484T > C (p.M64V) mutation caused complex I deficiency, diminished ATP production, increased production of reactive oxygen species (ROS), elevated apoptosis, and impaired mitophagy. Here, we investigated if the allotopic expression of human mitochondrial ND6 transgene corrected the mitochondrial dysfunctions due to LHON-associated m.14484T > C mutation. Methods Nucleus-versions of ND6 was generated by changing 6 non-universal codons with universal codons and added to mitochondrial targeting sequence of COX8. Stable transfectants were generated by transferring human ND6 cDNA expressed in a pCDH-puro vector into mutant cybrids carrying the m.14484T > C mutation and control cybrids. The effect of allotopic expression of ND6 on oxidative phosphorylation (OXPHOS) was evaluated using Blue Native gel electrophoresis and extracellular flux analyzer. Assessment of ROS production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analyses for apoptosis and mitophagy were undertaken via flow cytometry, TUNEL and immunofluorescence assays. Results The transfer of human ND6 into the cybrids carrying the m.14484T > C mutation raised the levels of ND6, ND1 and ND4L but did not change the levels of other mitochondrial proteins. The overexpression of ND6 led to 20~23% increases in the assembly and activity of complex I, and ~ 53% and ~ 33% increases in the levels of mitochondrial ATP and ΔΨm in the mutant cybrids bearing m.14484T > C mutation. Furthermore, mutant cybrids with overexpression of ND6 exhibited marked reductions in the levels of mitochondrial ROS. Strikingly, ND6 overexpression markedly inhibited the apoptosis process and restored impaired mitophagy in the cells carrying m.14484T > C mutation. However, overexpression of ND6 did not affect the ND6 level and mitochondrial functions in the wild-type cybrids, indicating that this ND6 level appeared to be the maximum threshold level to maintain the normal cell function. Conclusion We demonstrated that allotopic expression of nucleus-versions of ND6 restored complex I, apoptosis and mitophagy deficiencies caused by the m.14484T > C mutation. The restoration of m.14484T > C mutation-induced mitochondrial dysfunctions by overexpression of ND6 is a step toward therapeutic interventions for LHON and mitochondrial diseases.

Background: Mesenchymal stem cells (MSCs) hold promise for cell-based therapy, yet the sourcing, quality, and invasive methods of MSCs impede their mass production and quality control. Induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) can be infinitely expanded, providing advantages over conventional MSCs in terms of meeting unmet clinical demands. Methods: The potential of MSC therapy for Leber's hereditary optic neuropathy (LHON) remains uncertain. In this study, we used HLA-homozygous induced pluripotent stem cells to generate iMSCs using a defined protocol, and we examined their therapeutic potential in rotenone-induced LHON-like models in vitro and in vivo. Results: The iMSCs did not cause any tumorigenic incidence or inflammation-related lesions after intravitreal transplantation, and they remained viable for at least nine days in the mouse recipient's eyes. In addition, iMSCs exhibited significant efficacy in safeguarding retinal ganglion cells (RGCs) from rotenone-induced cytotoxicity in vitro, and they ameliorated CGL+IPL layer thinning and RGC loss in vivo. Optical coherence tomography (OCT) and an electroretinogram demonstrated that iMSCs not only prevented RGC loss and impairments to the retinal architecture, but they also improved retinal electrophysiology performance. Conclusion: The generation of iMSCs via the HLA homozygosity of iPSCs offers a compelling avenue for overcoming the current limitations of MSC-based therapies. The results underscore the potential of iMSCs when addressing retinal disorders, and they highlight their clinical significance, offering renewed hope for individuals affected by LHON and other inherited retinal conditions. [ABSTRACT FROM AUTHOR]

Background: Leber's hereditary optic neuropathy (LHON) is a rare disease. Large studies are difficult to conduct; therefore, case reports provide valuable data. Since 2015, patients have been treated with Idebenone. The aim of this paper is to share our experience with diagnosing and managing patients in different stages of LHON. Methods: We designed a case series study, including four patients undergoing genetic testing and ophthalmologic examination. Criteria for Idebenone administration and follow-up were presented. Results: All patients had mutation 11778G>A in MT-ND4. The first patient, an 82-year-old man, with long history of vision loss, had no indication for Idebenone. Two additional cases emerged within the same family: a 40-year-old brother and a 31-year-old sister. Both received Idebenone, with good outcomes only for the female. After a one-year regimen, they were lost to follow-up. The fourth patient, a 46-year-old man, was diagnosed in the subacute stage. Idebenone administration was deferred, allowing progression of visual field defects. After 17 months of treatment, visual improvement appeared. The treatment was continued for 36 months, with short interruptions, resulting in good outcomes. Conclusions: Our study demonstrated positive results with long-term Idebenone use. Contrary to medical literature, our female patient had a favorable evolution, despite the delayed diagnosis. [ABSTRACT FROM AUTHOR]

A 29-year-old female with no family history presented with bilateral progressive blurred vision. Her symptoms appeared at 12-years-old and her visual acuity had since deteriorated from 0.6 to 0.2 bilaterally with decreased critical flicker frequency and bilateral central scotomas. She did not have a relative afferent pupillary defect. Fundoscopy revealed no distinct disc hyperaemia, atrophy, or peripapillary telangiectatic vessels. The retinal nerve fibre layer appeared normal on optical coherence tomography in each eye; however, loss of the interdigitation zone and the disruption of the ellipsoid zone at the fovea were observed in both eyes. Multifocal electroretinography revealed decreased amplitudes at both macula regions. Mitochondrial deoxyribonucleic acid analysis identified an m.14502T>C mutation, one of the primary mutations causing Leber's hereditary optic neuropathy (LHON). Despite the presence of a marked LHON mutation, however, she was clinically diagnosed as having an occult macular dystrophy. There have only been five previous case reports, all of which were sporadic, which detail the clinical characteristics of the m.14502T>C mutation. The m.14502T>C phenotype is somewhat consistent with that of the other major mutations, including young onset, bilateral progressive visual impairment, and a typical LHON fundus. Nevertheless, m.14502T>C alone has an extremely low penetrance and its phenotype may be minimal or subclinical, as seen in our case. Since little is known about the clinical course of the m.14502T>C mutation it may be possible that the LHON phenotype may appear in later stages of life. Moreover, m.14502T>C may function as a modifier gene, which alters the phenotype of other coexisting major LHON mutations, including penetrance and the severity of the disease, through synergistic effects. [ABSTRACT FROM AUTHOR]

Purpose: The study aimed to unravel abnormal cerebral blood flow (CBF) in patients with Leber's hereditary optic neuropathy (LHON) using arterial spin labeling (ASL) and to investigate the associations among disrupted CBF, disease duration, and neuro-ophthalmological impairment. Methods: ASL perfusion imaging data was collected from 20 patients with acute LHON, 29 patients with chronic LHON, and 37 healthy controls. We used a one-way analysis of covariance to test the intergroup differences in CBF. Linear and nonlinear curve fit models were applied to explore the associations among CBF, disease duration, and neuro-ophthalmological metrics. Results: Brain regions differed in LHON patients, including the left sensorimotor and bilateral visual areas (p < 0.05, cluster-wise family-wise error correction). Acute and chronic LHON patients demonstrated lower CBF in bilateral calcarine than the healthy controls. Chronic LHON had lower CBF in the left middle frontal gyrus and sensorimotor cortex, and temporal-partial junction than the healthy controls and acute LHON. A significant logarithmic negative correlation was shown between CBF of left middle frontal gyrus and disease duration. A significant linear positive correlation was found between retinal nerve fiber layer thickness and CBF in left middle frontal gyrus, and negative correlations between loss of variance and CBF in left middle frontal gyrus and sensorimotor cortex (p < 0.05, Bonferroni correction). Conclusion: LHON patients exhibited reduced CBF in the visual pathway, sensorimotor and higher-tier cognitive areas. Disease duration and neuro-ophthalmological impairments can influence the metabolism of non-visual areas. [ABSTRACT FROM AUTHOR]

Mutations to the ND5 gene are uncommonly associated with Leber’s hereditary optic neuropathy (LHON). Herein, we describe a 57-year-old man with the m. 13528A>G, p. (Thr398Ala) mutation at the ND5 gene who presented with progressive bilateral vision loss over the course of 3 months. He had a significant history of smoking and alcohol consumption. Visual field testing demonstrated bilateral central scotomas. At 2-year follow-up, his visual acuity improved relative to baseline and temporal optic disc pallor was observed in both eyes. There are scarce reports of this mutation in the literature, and this case report further expands the clinical presentation of the m. 13528A>G mutation at the ND5 gene in patients with LHON phenotype.

Optic neuropathies are characterized by the degeneration of the optic nerves and represent a considerable individual and societal burden. Notably, Leber’s hereditary optic neuropathy (LHON) is a devastating vision disease caused by mitochondrial gene mutations that hinder oxidative phosphorylation and increase oxidative stress, leading to the loss of retinal ganglion neurons and axons. Loss of vision is rapid and severe, predominantly in young adults. Penetrance is incomplete, and the time of onset is unpredictable. Recent findings revealed that the incidence of genetic LHON susceptibility is around 1 in 1000, much higher than believed till now. Environmental factors are critical in LHON triggering or severity. Families at risk have a very strong demand for how to prevent the onset or limit the severity of the disease. Here, we review recent knowledge of the extrinsic determinants of LHON expression, including lifestyle, dietary supplements, common chemicals, and drugs.

Leber's hereditary optic neuropathy (LHON) is a disease that affects the optical nerve, causing visual loss. The diagnosis of LHON is mostly defined by the identification of three pathogenic variants in the mitochondrial DNA. Idebenone is widely used to treat LHON patients, but only some of them are responders to treatment. In our study, we assessed the maximal respiration rate (MRR) and other respiratory parameters in eight fibroblast lines from subjects carrying LHON pathogenic variants. We measured also the effects of idebenone treatment on cell growth and mtDNA amounts. Results showed that LHON fibroblasts had significantly reduced respiratory parameters in untreated conditions, but no significant gain in MRR after idebenone supplementation. No major toxicity toward mitochondrial function and no relevant compensatory effect in terms of mtDNA quantity were found for the treatment at the tested conditions. Our findings confirmed that fibroblasts from subjects harboring LHON pathogenic variants displayed impaired respiration, regardless of the disease penetrance and severity. Testing responsiveness to idebenone treatment in cultured cells did not fully recapitulate in vivo data. The in-depth evaluation of cellular respiration in fibroblasts is a good approach to evaluating novel mtDNA variants associated with LHON but needs further evaluation as a potential biomarker for disease prognosis and treatment responsiveness. [ABSTRACT FROM AUTHOR]

Background: Leber's hereditary optic neuropathy (LHON) is a maternally inherited eye disease due to mutations in mitochondrial DNA. However, there is no effective treatment for this disease. LHON-linked ND6 14484T > C (p.M64V) mutation caused complex I deficiency, diminished ATP production, increased production of reactive oxygen species (ROS), elevated apoptosis, and impaired mitophagy. Here, we investigated if the allotopic expression of human mitochondrial ND6 transgene corrected the mitochondrial dysfunctions due to LHON-associated m.14484T > C mutation. Methods: Nucleus-versions of ND6 was generated by changing 6 non-universal codons with universal codons and added to mitochondrial targeting sequence of COX8. Stable transfectants were generated by transferring human ND6 cDNA expressed in a pCDH-puro vector into mutant cybrids carrying the m.14484T > C mutation and control cybrids. The effect of allotopic expression of ND6 on oxidative phosphorylation (OXPHOS) was evaluated using Blue Native gel electrophoresis and extracellular flux analyzer. Assessment of ROS production in cell lines was performed by flow cytometry with MitoSOX Red reagent. Analyses for apoptosis and mitophagy were undertaken via flow cytometry, TUNEL and immunofluorescence assays. Results: The transfer of human ND6 into the cybrids carrying the m.14484T > C mutation raised the levels of ND6, ND1 and ND4L but did not change the levels of other mitochondrial proteins. The overexpression of ND6 led to 20~23% increases in the assembly and activity of complex I, and ~ 53% and ~ 33% increases in the levels of mitochondrial ATP and ΔΨm in the mutant cybrids bearing m.14484T > C mutation. Furthermore, mutant cybrids with overexpression of ND6 exhibited marked reductions in the levels of mitochondrial ROS. Strikingly, ND6 overexpression markedly inhibited the apoptosis process and restored impaired mitophagy in the cells carrying m.14484T > C mutation. However, overexpression of ND6 did not affect the ND6 level and mitochondrial functions in the wild-type cybrids, indicating that this ND6 level appeared to be the maximum threshold level to maintain the normal cell function. Conclusion: We demonstrated that allotopic expression of nucleus-versions of ND6 restored complex I, apoptosis and mitophagy deficiencies caused by the m.14484T > C mutation. The restoration of m.14484T > C mutation-induced mitochondrial dysfunctions by overexpression of ND6 is a step toward therapeutic interventions for LHON and mitochondrial diseases. [ABSTRACT FROM AUTHOR]

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Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies. [ABSTRACT FROM AUTHOR]

OCTA imaging in optic neuropathies.

• We analyzed the functional and structural changes in retinal ganglion cells (RGCs) and their axons in patients affected by Leber's hereditary optic neuropathy (LHON) using photopic negative response (PhNR) and spectral domain optical coherence tomography (SD-OCT). • The functional and structural changes in RGCs and their axons in LHON asymptomatic carriers have also been evaluated. • In addition, affected individuals were divided into subacute, dynamic and chronic phases based on disease duration in order to evaluate the decay in RGCs function and structure. To analyze the functional and structural changes in retinal ganglion cells (RGCs) and their axons that occur during Leber's hereditary optic neuropathy (LHON) using photopic negative response (PhNR) and spectral domain optical coherence tomography (SD-OCT). Individuals diagnosed with LHON and their family members were invited to participate in this cross-sectional study. PhNR and OCT were used. The PhNR amplitude and peripapillary retinal nerve fiber layer (pRNFL) thicknesses were compared among the three groups. In addition, affected individuals were divided into subacute, dynamic and chronic phases based on disease duration in order to evaluate the decay in RGCs function and structure. 73 affected and 30 carriers with a m.11778G > A mutation were included. PhNR amplitude and the thickness of pRNFL significantly decreased in affected individuals and carriers compared to that of the controls (P＜0.001). However, there was no difference between the carriers and the controls (P＞0.05). There was no difference in the PhNR amplitude of different phases (P = 0.464). In the subacute phase, only temporal pRNFL thickness decreased significantly (P＜0.001). PRNFL thickness decreased significantly in dynamic phase (P＜0.001). Temporal pRNFL thickness continued to decrease in the chronic phase (P = 0.042). In the subacute phase, the function of RGCs was severely impaired. Thickness of pRNFL decreased significantly in four quadrants during disease progression. In the chronic phase, pRNFL thickness decreased slightly. Carriers have shown RGCs dysfunction before pathological changes occur, suggesting subclinical abnormalities. [ABSTRACT FROM AUTHOR]

Mutations to the ND5 gene are uncommonly associated with Leber’s hereditary optic neuropathy (LHON). Herein, we describe a 57-year-old man with the m. 13528A>G, p. (Thr398Ala) mutation at the ND5 gene who presented with progressive bilateral vision loss over the course of 3 months. He had a significant history of smoking and alcohol consumption. Visual field testing demonstrated bilateral central scotomas. At 2-year follow-up, his visual acuity improved relative to baseline and temporal optic disc pallor was observed in both eyes. There are scarce reports of this mutation in the literature, and this case report further expands the clinical presentation of the m. 13528A>G mutation at the ND5 gene in patients with LHON phenotype. [ABSTRACT FROM AUTHOR]

Leber’s hereditary optic neuropathy (LHON) is a rare maternally inherited disease caused by mutations in mitochondrial DNA (mtDNA) genes encoding subunits of complex I in the mitochondrial respiratory chain. The most common mutations causing LHON are G11778A, G3460A and T14484C, but there are also several less common mutations. LHON presents as acute or subacute bilateral visual loss, usually affecting young males. The aim of this study was to assess the clinical symptomatology and genetic analysis of Bulgarian patients with LHON. Twenty-two patients were diagnosed with LHON based on clinical evaluation and genetic examination (17 males and 5 females); 12 of them were previously reported, while 8 males and 2 females are newly diagnosed. A full neuroophthalmologic and genetic examination was performed. Eight patients had a family history of LHON, while 14 were isolated cases. The age at onset ranged from 3 to 43 years, and visual acuity ranged from counting fingers to 0.9. Genetic testing revealed various mutations, including a rare mutation G3635A in MT-ND1 in five affected members of one pedigree and digenic inheritance of G11778A and T14484C in three individuals from a different family. A variant m.15988A > G in the mitochondrial gene MT-TP with a high level of heteroplasmy was found in one patient. In addition to the most common mutations causing LHON, our patients also had rare mutations. These results suggest that genetic analysis of the entire mtDNA sequence is recommended in cases with strong clinical suspicion of LHON, since new rare mtDNA pathogenic variants are being identified.

The study aimed to investigate the neurovascular coupling abnormalities in Leber's hereditary optic neuropathy (LHON) and their associations with clinical manifestations. Twenty qualified acute Leber's hereditary optic neuropathy (A-LHON, disease duration ≤ 1 year), 29 chronic Leber's hereditary optic neuropathy (C-LHON, disease duration > 1 year), as well as 37 healthy controls (HCs) were recruited. The neurovascular coupling strength was quantified as the ratio between regional homogeneity (ReHo), which represents intrinsic neuronal activity and relative cerebral blood flow (CBF), representing microcirculatory blood supply. A one-way analysis of variance was used to compare intergroup differences in ReHo/CBF ratio with gender and age as co-variables. Pearson's Correlation was used to clarify the association between ReHo, CBF, and neurovascular coupling strength. Furthermore, we applied linear and exponential non-linear regression models to explore the associations among ReHo/CBF, disease duration, and neuroophthalmological metrics. Compared with HCs, A_LHON, and C_LHON patients demonstrated a higher ReHo/CBF ratio than the HCs in the bilateral primary visual cortex (B_CAL), which was accompanied by reduced CBF while preserved ReHo. Besides, only C_LHON had a higher ReHo/CBF ratio and reduced CBF in the left middle temporal gyrus (L_MTG) and left sensorimotor cortex (L_SMC) than the HCs, which was accompanied by increased ReHo in L_MTG (p < 1.85e-3, Bonferroni correction). A-LHON and C-LHON showed a negative Pearson correlation between ReHo/CBF ratio and CBF in B_CAL, L_SMC, and L_MTG. Only C_LHON showed a weak positive correlation between ReHo/CBF ratio and ReHo in L_SMC and L_MTG (p < 0.05, uncorrected). Finally, disease duration was positively correlated with ReHo/CBF ratio of L_SMC (Exponential: Radj2 = 0.23, p = 8.66e-4, Bonferroni correction). No statistical correlation was found between ReHo/CBF ratio and neuro-ophthalmological metrics (p > 0.05, Bonferroni correction). Brain neurovascular "dyscoupling" within and outside the visual system might be an important neurological mechanism of LHON. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON) is a rare maternally inherited disease caused by mutations in mitochondrial DNA (mtDNA) genes encoding subunits of complex I in the mitochondrial respiratory chain. The most common mutations causing LHON are G11778A, G3460A and T14484C, but there are also several less common mutations. LHON presents as acute or subacute bilateral visual loss, usually affecting young males. The aim of this study was to assess the clinical symptomatology and genetic analysis of Bulgarian patients with LHON. Twenty-two patients were diagnosed with LHON based on clinical evaluation and genetic examination (17 males and 5 females); 12 of them were previously reported, while 8 males and 2 females are newly diagnosed. A full neuroophthalmologic and genetic examination was performed. Eight patients had a family history of LHON, while 14 were isolated cases. The age at onset ranged from 3 to 43 years, and visual acuity ranged from counting fingers to 0.9. Genetic testing revealed various mutations, including a rare mutation G3635A in MT-ND1 in five affected members of one pedigree and digenic inheritance of G11778A and T14484C in three individuals from a different family. A variant m.15988A > G in the mitochondrial gene MT-TP with a high level of heteroplasmy was found in one patient. In addition to the most common mutations causing LHON, our patients also had rare mutations. These results suggest that genetic analysis of the entire mtDNA sequence is recommended in cases with strong clinical suspicion of LHON, since new rare mtDNA pathogenic variants are being identified. [ABSTRACT FROM AUTHOR]

The blood supply in the retina ensures photoreceptor function and maintains regular vision. Leber's hereditary optic neuropathy (LHON), caused by the mitochondrial DNA mutations that deteriorate complex I activity, is characterized by progressive vision loss. Although some reports indicated retinal vasculature abnormalities as one of the comorbidities in LHON, the paracrine influence of LHON-affected retinal ganglion cells (RGCs) on vascular endothelial cell physiology remains unclear. To address this, we established an in vitro model of mitochondrial complex I deficiency using induced pluripotent stem cell-derived RGCs (iPSC-RGCs) treated with a mitochondrial complex I inhibitor rotenone (Rot) to recapitulate LHON pathologies. The secretomes from Rot-treated iPSC-RGCs (Rot-iPSC-RGCs) were collected, and their treatment effect on human umbilical vein endothelial cells (HUVECs) was studied. Rot induced LHON-like characteristics in iPSC-RGCs, including decreased mitochondrial complex I activity and membrane potential, and increased mitochondrial reactive oxygen species (ROS) and apoptosis, leading to mitochondrial dysfunction. When HUVECs were exposed to conditioned media (CM) from Rot-iPSC-RGCs, the angiogenesis of HUVECs was suppressed compared to those treated with CM from control iPSC-RGCs (Ctrl-iPSC-RGCs). Angiogenesis-related proteins were altered in the secretomes from Rot-iPSC-RGC-derived CM, particularly angiopoietin, MMP-9, uPA, collagen XVIII, and VEGF were reduced. Notably, GeneMANIA analysis indicated that VEGFA emerged as the pivotal angiogenesis-related protein among the identified proteins secreted by health iPSC-RGCs but reduced in the secretomes from Rot-iPSC-RGCs. Quantitative real-time PCR and western blots confirmed the reduction of VEGFA at both transcription and translation levels, respectively. Our study reveals that Rot-iPSC-RGCs establish a microenvironment to diminish the angiogenic potential of vascular cells nearby, shedding light on the paracrine regulation of LHON-affected RGCs on retinal vasculature. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells (MSCs) hold promise for cell-based therapy, yet the sourcing, quality, and invasive methods of MSCs impede their mass production and quality control. Induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) can be infinitely expanded, providing advantages over conventional MSCs in terms of meeting unmet clinical demands. Methods: The potential of MSC therapy for Leber’s hereditary optic neuropathy (LHON) remains uncertain. In this study, we used HLA-homozygous induced pluripotent stem cells to generate iMSCs using a defined protocol, and we examined their therapeutic potential in rotenone-induced LHON-like models in vitro and in vivo. Results: The iMSCs did not cause any tumorigenic incidence or inflammation-related lesions after intravitreal transplantation, and they remained viable for at least nine days in the mouse recipient’s eyes. In addition, iMSCs exhibited significant efficacy in safeguarding retinal ganglion cells (RGCs) from rotenone-induced cytotoxicity in vitro, and they ameliorated CGL+IPL layer thinning and RGC loss in vivo. Optical coherence tomography (OCT) and an electroretinogram demonstrated that iMSCs not only prevented RGC loss and impairments to the retinal architecture, but they also improved retinal electrophysiology performance. Conclusion: The generation of iMSCs via the HLA homozygosity of iPSCs offers a compelling avenue for overcoming the current limitations of MSC-based therapies. The results underscore the potential of iMSCs when addressing retinal disorders, and they highlight their clinical significance, offering renewed hope for individuals affected by LHON and other inherited retinal conditions.

Background: Leber’s hereditary optic neuropathy (LHON) is a rare disease. Large studies are difficult to conduct; therefore, case reports provide valuable data. Since 2015, patients have been treated with Idebenone. The aim of this paper is to share our experience with diagnosing and managing patients in different stages of LHON. Methods: We designed a case series study, including four patients undergoing genetic testing and ophthalmologic examination. Criteria for Idebenone administration and follow-up were presented. Results: All patients had mutation 11778G>A in MT-ND4. The first patient, an 82-year-old man, with long history of vision loss, had no indication for Idebenone. Two additional cases emerged within the same family: a 40-year-old brother and a 31-year-old sister. Both received Idebenone, with good outcomes only for the female. After a one-year regimen, they were lost to follow-up. The fourth patient, a 46-year-old man, was diagnosed in the subacute stage. Idebenone administration was deferred, allowing progression of visual field defects. After 17 months of treatment, visual improvement appeared. The treatment was continued for 36 months, with short interruptions, resulting in good outcomes. Conclusions: Our study demonstrated positive results with long-term Idebenone use. Contrary to medical literature, our female patient had a favorable evolution, despite the delayed diagnosis.

Leber’s hereditary optic neuropathy (LHON) is a fairly prevalent mitochondrial disorder (1:50,000) arising from the dysfunction of the mitochondrial respiratory chain, which eventually leads to apoptosis of retinal ganglion cells. The usual presentation is that of a young male with a sequential reduction in visual acuity. OCT has been used to study the pattern of optic nerve involvement in LHON, showing early thickening of the inferior and superior retinal nerve fibre layer and ganglion cell layer thinning corresponding with the onset of symptoms. Of the three primary mutations for LHON, the m.14484T>C mutation has the best visual prognosis. Recent emerging therapeutic options for LHON include idebenone and the introduction of genetic vector therapy, which is currently in phase III clinical trials. Screening of family members and adequate advice to avoid environmental triggers, such as smoking and alcohol consumption, are also cornerstones in the management of LHON.

Objective: To elucidate the clinical, radiologic characteristics of Leber’s hereditary optic neuropathy (LHON) associated with the other diseases. Materials and methods: Clinical data were retrospectively collected from hospitalized patients with LHON associated with the other diseases at the Neuro-Ophthalmology Department at the Chinese People’s Liberation Army General Hospital (PLAGH) from December 2014 to October 2018. Results: A total of 13 patients, 24 eyes (10 men and 3 women; mean age, 30.69 ± 12.76 years) with LHON mitochondrial DNA (mtDNA) mutations, were included in the cohort. 14502(5)11778(4)11778 &11696(1)12811(1)11696(1)3460(1). One patient was positive for aquaporin-4 antibody (AQP4-Ab), and two were positive for myelin oligodendrocyte glycoprotein antibody (MOG-Ab). Three patients were associated with idiopathic optic neuritis (ON). Two patients were with compression optic neuropathy. Three patients were with the central nervous system (CNS) diseases. One patient was with proliferative diabetic retinopathy (PDR) and one with idiopathic orbital inflammatory syndrome (IOIS). At the onset, visual acuity (VA) in eighteen eyes was below 0.1, one eye was 0.5, five eyes were above 0.5, while VA in sixteen eyes was below a 0.1 outcome, three eyes experienced moderate vision loss. MRI images showed T2 lesions and enhancement in nine patients who received corticosteroids treatment; additional immune modulators treatment was performed on two patients. None of the patients had relapse during the follow-up time. Conclusion: Leber’s hereditary optic neuropathy can be accompanied with multiple-related diseases, especially different subtypes of ON, which were also exhibited with IOIS and compression optic neuropathy for the first time in this cohort. This condition may be a distinct entity with an unusual clinical and therapeutic profile. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disease caused by mitochondria DNA (mtDNA) mutation. It is characterized by acute and subacute visual loss predominantly affecting young men. The mtDNA mutation is transmitted to all maternal lineages. However, only approximately 50% of men and 10% of women harboring a pathogenic mtDNA mutation develop optic neuropathy, reflecting both the incomplete penetrance and its unexplained male prevalence, where over 80% of patients are male. Nuclear modifier genes have been presumed to affect the penetrance of LHON. With conventional genetic methods, prior studies have failed to solve the underlying pathogenesis. Whole exome sequencing (WES) is a new molecular technique for sequencing the protein-coding region of all genes in a whole genome. We performed WES from five families with 17 members. These samples were divided into the proband group (probands with acute onset of LHON, n = 7) and control group (carriers including mother and relative carriers with mtDNSA 11778 mutation, without clinical manifestation of LHON, n = 10). Through whole exome analysis, we found that many mitochondria related (MT-related) nuclear genes have high percentage of variants in either the proband group or control group. The MT genes with a difference over 0.3 of mutation percentage between the proband and control groups include AK4, NSUN4, RDH13, COQ3, and FAHD1. In addition, the pathway analysis revealed that these genes were associated with cofactor metabolism pathways. Family-based analysis showed that several candidate MT genes including METAP1D (c.41G > T), ACACB (c.1029del), ME3 (c.972G > C), NIPSNAP3B (c.280G > C, c.476C > G), and NSUN4 (c.4A > G) were involved in the penetrance of LHON. A GWAS (genome wide association study) was performed, which found that ADGRG5 (Chr16:575620A:G), POLE4 (Chr2:7495872T:G), ERMAP (Chr1:4283044A:G), PIGR (Chr1:2069357C:T;2069358G:A), CDC42BPB (Chr14:102949A:G), PROK1 (Chr1:1104562A:G), BCAN (Chr 1:1566582C:T), and NES (Chr1:1566698A:G,1566705T:C, 1566707T:C) may be involved. The incomplete penetrance and male prevalence are still the major unexplained issues in LHON. Through whole exome analysis, we found several MT genes with a high percentage of variants were involved in a family-based analysis. Pathway analysis suggested a difference in the mutation burden of MT genes underlining the biosynthesis and metabolism pathways. In addition, the GWAS analysis also revealed several candidate nuclear modifier genes. The new technology of WES contributes to provide a highly efficient candidate gene screening function in molecular genetics. [ABSTRACT FROM AUTHOR]

Background: Optic neuropathy has become a new typical syndromic multi-system disease that leads to optic atrophy. This review discusses potential treatments and advances of Leber's hereditary optic neuropathy (LHON), a sporadic genetic disorder. LHON is caused due to slight mutations in mitochondria leading to mitochondrial dysfunction, causing vision loss. There are no current significant treatments that have been proven to work for LHON. Methods: However, extensive review was carried out on capable studies that have shown potential treatment sensory systems and are being evaluated currently. Some of these studies are in clinical trials, whereas other ones are still being planned. Here, we focus more on treatment based on mesenchymal stem cells-mediated mitochondrial transfer via various techniques. We discuss different mitochondrial transfer modes and possible ways to understand the mitochondria transfer technique's phenotypic characteristics. Conclusion: It is clearly understood that transfer of healthy mitochondria from MSC to target cell would regulate the range of reactive oxygen species and ATP'S, which are majorly responsible for mutation upon irregulating. Therefore, mitochondrial transfer is suggested and discussed in this review with various aspects. The graphical abstract represents different means of mitochondrial transport like (a) Tunnelling nanotubules, (b) Extracellular vesicles, (c) Cell fusion and (d) Gap junctions. In (a) Tunnelling nanotubules, the signalling pathways TNF- α/TNF αip2 and NFkB/TNF αep2 are responsible for forming tunnels. Also, Miro protein acts as cargo for the transport of mitochondria with myosin's help in the presence of RhoGTPases [35]. In (b) Extracellular vesicles, the RhoA ARF6 contributes to Actin/Cytoskeletal rearrangement leading to the shedding of microvesicles. Coming to (c) Cell fusion when there is a high amount of ATP, the cells tend to fuse when in close proximity leading to the transfer of mitochondria via EFF-1/HAP2 [48]. In (d) Gap Junctions, Connexin43 is responsible for the intracellular channel in the presence of more ATP [86]. [ABSTRACT FROM AUTHOR]

Leber's hereditary optic neuropathy (LHON), a maternally inherited ocular disease, is predominantly caused by mitochondrial DNA (mtDNA) mutations. Mitochondrial tRNA variants are hypothesized to amplify the pathogenic impact of three primary mutations. However, the exact mechanisms remained unclear. In the present study, the synergistic effect of the tRNA Glu 14693A > G and ND6 14484T > C mutations in three Chinese families affected by LHON is investigated. The m.14693A > G mutation nearly abolishes the pseudouridinylation at position 55 of tRNA Glu , leading to structural abnormalities, decreased stability, aberrant mitochondrial protein synthesis, and increased autophagy. In contrast, the ND6 14484T > C mutation predominantly impairs complex I function, resulting in heightened apoptosis and virtually no induction of mitochondrial autophagy compared to control cell lines. The presence of dual mutations in the same cell lines exhibited a coexistence of both upregulated cellular stress responses to mitochondrial damage, indicating a scenario of autophagy and mutation dysregulation within these dual-mutant cell lines. The data proposes a novel hypothesis that mitochondrial tRNA gene mutations generally lead to increased mitochondrial autophagy, while mutations in genes encoding mitochondrial proteins typically induce apoptosis, shedding light on the intricate interplay between different genetic factors in the manifestation of LHON., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)