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Nutritional Optic Neuropathy
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
William Sultan, Giulia Amore, Uchenna Francis Nwako, Stacey Aquino Cohitmingao, Samuel Asanad, Alfredo Sadun
LHON is caused by point mutations in the mitochondrial DNA, affecting predominantly young males in their late teens or twenties who experience a sudden onset of severe vision loss. DOA is mainly due to mutations in the nuclear OPA1 gene and affects equally males and females from childhood, with a more indolent course [19,20].
Leber's Hereditary Optic Neuropathy (LHON)/ Leber's Optic Atrophy (LOA)
Published in Charles Theisler, Adjuvant Medical Care, 2023
LHON is an inherited mitochondrial disorder that affects men (60%-90%) more than women and leads to painless subacute loss of central vision. The condition usually begins in an individual's teens or twenties. Loss of visual acuity (blurring or clouding) and color vision are usually the first symptoms of LHON. The condition mainly affects central vision and significantly interferes with reading, writing, driving, and recognizing faces and colors, as well as doing close-up work (e.g., reading, cooking, or fixing things). Even if symptoms start in one eye, both eyes are eventually affected. Although central vision improves in a small percentage of cases, no generally accepted measures have been shown either to prevent or delay the onset of blindness.1
Clinical Perspectives on Gene Therapy for Retinal and Eye Diseases
Published in Yashwant Pathak, Gene Delivery, 2022
Devika S. Joshi, Gaurav M. Karve, Shrikant D. Joshi
Gene therapy for LHON is still under clinical trials. One such trial in Phase I, involving adeno-associated virus as a vector of different doses has shown slight improvement in the visual loss of LHON subjects with G11778A mutation of ND4.11
The epidemiology and mutation types of Leber’s hereditary optic neuropathy in Thailand
Published in Annals of Medicine, 2022
Kanchalika Sathianvichitr, Benjaporn Sigkaman, Niphon Chirapapaisan, Poramaet Laowanapiban, Tanyatuth Padungkiatsagul, Supanut Apinyawasisuk, Juthamat Witthayaweerasak, Wanicha Chuenkongkaew
In recent years, genetic testing has played a crucial role in LHON diagnosis. The testing focuses on three common mutations, G11778A, T14484C, and G3460A, which account for more than 95% of cases [6]. These missense mutations occur in mitochondrial DNA (mtDNA). They code a subunit of the respiratory chain complex I, leading to free radical accumulation and cell apoptosis [6]. Another positive attribute of genetic testing is its prognostic capability. While the G11778A mutation produces the most severe visual loss with the poorest recovery, the visual loss caused by T14484C has the best chance of recovery. In contrast to other mitochondrial diseases, maternal inheritance in LHON patients manifest incomplete penetration and a male predominance. The reasons for this are not well established. Several studies [7–9] proposed that environmental factors such as smoking and alcohol consumption, hormonal factors and genetic modifiers including secondary mutations and haplogroup status are involved.
The Natural History of Leber’s Hereditary Optic Neuropathy in an Irish Population and Assessment for Prognostic Biomarkers
Published in Neuro-Ophthalmology, 2022
Kirk A. J. Stephenson, Joseph McAndrew, Paul F. Kenna, Lorraine Cassidy
Our main findings were that female gender (p = .198), mtDNA homoplasmy (regardless of variant, p = .092), presenting with ‘off-chart’ VA (p = .068), telangiectatic or atrophic discs (p = .012), non-recordable pVEP (p = .175), and thinner nasal RNFL measurements (p = .016) were useful as biomarkers predicting poorer (i.e., ‘off-chart’) final VA. Those presenting < 20 years of age and with ‘on-chart’ VA had better visual outcomes and those with normal or swollen discs were more likely to improve by ≥ 15 letters. Despite this, LHON still has a universally dismal visual prognosis.11 mtDNA heteroplasmy was a useful biomarker of idebenone response, but idebenone treatment was not statistically significantly associated with better visual outcomes. However, one idebenone-treated patient recovered legal driving vision and others reported functional improvement in vision and currently this is the only approved therapeutic option for LHON.
Genetic diseases mimicking multiple sclerosis
Published in Postgraduate Medicine, 2021
Chueh Lin Hsu, Piotr Iwanowski, Chueh Hsuan Hsu, Wojciech Kozubski
Clinical features of LHON are characterized by painless, subacute vision loss. It may start from one eye and progress to involve both eyes after weeks or months [214]. Rarely is a patient present with unilateral eye involvement. Most patients lose their vision before 50 years of age. Males are around five times more likely to be affected than females [215]. Blurring and clouding vision in the central visual field are usually the symptoms of onset, followed by loss of color vision over time. Blindness and optic atrophies are the end presentations [214-216]. Some LHON patients present with additional extraocular manifestations such as cardiac arrhythmias, myopathy, peripheral neuropathy, and tremors, which resemble that of MS, and is thus termed LHON-MS, also known as Harding syndrome [217-219].