Clinical Case Notes

Sugisaka, Eiko; Ohde, Hisao; Shinoda, Kei; Mashima, Yukihiko

doi:10.1111/j.1442-9071.2007.01628.x

Cited by 19 publications

(5 citation statements)

References 7 publications

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“…In this short cohort, the unilateral loss of vision appears in all patients, in adulthood according as described in several studies [14]. Progressively, the second eye becomes involved, with a median delay of 7-8 weeks.…”

Section: Clinical Characteristics Of Lhon Patientssupporting

confidence: 53%

Respiratory Chain Complex I Deficiency in Leber Hereditary Optic Neuropathy: Insights from Ophthalmologic and Molecular Investigations in Tunisia

Chkioua,

Amri,

Sahli

et al. 2024

Preprint

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Background Leber hereditary optic neuropathy (LHON) is a mitochondrial DNA (mtDNA) rare disease due to the mutation of the NADH dehydrogenase enzyme. LHON is characterized by a sudden central vision loss due to focal degeneration of the retinal ganglion cell layer and optic nerve. Symptoms usually appear between the age of 18 and 35 years. Some individuals present the mtDNA mutations but do not express this disease. The heteroplasmic or homoplasmic character of the mutations among patients explains why they develop the disease or not even though they carry the mutation. Methods This study was performed in collaboration with the department of ophthalmology of Farhat Hached Hospital, Sousse, Tunisia. Screening for the common mutations in ND1 gene (mt.3460G > A), ND4 gene (mt.11778G > A) and ND6 gene (mt.14484T > C) was performed in five Tunisian families by standard RFLP PCR, followed by direct sequencing of the entire of these genes. Indeed, bioinformatics tools were used to predict the potential functional impact of the identified mutations on the Human mitochondrial respiratory complex I protein. Results one novel p.Leu601Met (m.14137C > A), and four previously reported mutations were identified in this study including: rs199476112G > A (m.11778G > A); rs202227543G > A (m.14258G > A); m.3244G > C, rs1603224763 (m.14510 dup) and NC_012920.1:m.3244G > C. In this present report, only one patient was found carrying the primary point mutation (m.G11778A). The ophthalmologic findings showing major fundus changes included hyperemic optic discs; disc pseudo-oedema and microangiopathy leading to optic disc atrophy. The analyses of the stability of protein upon identified mutations using DynaMut tool server demonstrated that these variations induce a rigidification in the region where they are located. Conclusion This is the first Tunisian report of mtDNA mutations identified in Tunisia causing the LHON. The main factors involved in the pathophysiological mechanisms of this disease are genetic, epigenetic, hormonal and environmental influences.

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Section: Clinical Characteristics Of Lhon Patientssupporting

confidence: 53%

Respiratory Chain Complex I Deficiency in Leber Hereditary Optic Neuropathy: Insights from Ophthalmologic and Molecular Investigations in Tunisia

Chkioua,

Amri,

Sahli

et al. 2024

Preprint

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“…In fact, one case is reported of an 18-year interval between eye involvement (Ohden et al, 2016). Unilateral cases are very rare, but have been reported (Nikoskelainen et al, 1996;Sugisaka et al, 2007).…”

Section: Hereditary Optic Neuropathiesmentioning

confidence: 99%

Lateral thinking – Interocular symmetry and asymmetry in neurovascular patterning, in health and disease

Cameron

Megaw

Tatham

et al. 2017

Progress in Retinal and Eye Research

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No biological system or structure is likely to be perfectly symmetrical, or have identical right and left forms. This review explores the evidence for eye and visual pathway asymmetry, in health and in disease, and attempts to provide guidance for those studying the structure and function of the visual system, where recognition of symmetry or asymmetry may be essential. The principal question with regards to asymmetry is not 'are the eyes the same?', for some degree of asymmetry is pervasive, but 'when are they importantly different?'. Knowing if right and left eyes are 'importantly different' could have significant consequences for deciding whether right or left eyes are included in an analysis or for examining the association between a phenotype and ocular parameter. The presence of significant asymmetry would also have important implications for the design of normative databases of retinal and optic nerve metrics. In this review, we highlight not only the universal presence of asymmetry, but provide evidence that some elements of the visual system are inherently more asymmetric than others, pointing to the need for improved normative data to explain sources of asymmetry and their impact on determining associations with genetic, environmental or health-related factors and ultimately in clinical practice.

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“…The three patients in this report therefore represent relatively late-onset cases, raising some rather intriguing questions as to the possible triggers for visual loss in these otherwise healthy m.11778G>A mutation carriers. Unilateral optic neuropathy has been described only rarely in LHON [6], [12]–[15], and it is tempting to draw a possible causal link between the atypical, unilateral clinical course in Patient 1 and the finding of a markedly raised intraocular pressure in the affected right eye. Over a four-year follow-up period, the left eye has remained uninvolved with normal intraocular pressures without treatment.…”

Section: Discussionmentioning

confidence: 99%

Raised Intraocular Pressure as a Potential Risk Factor for Visual Loss in Leber Hereditary Optic Neuropathy

et al. 2013

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Leber Hereditary Optic Neuropathy (LHON) is an important cause of inherited mitochondrial blindness among young adults. The majority of patients carry one of three mitochondrial DNA (mtDNA) point mutations: m.3460G>A, m.11778G>A and m.14484T>C, all of which affect critical complex I subunits of the mitochondrial respiratory chain. LHON is characterised by marked incomplete penetrance, clearly implying that the mtDNA mutation is insufficient on its own to trigger retinal ganglion cell dysfunction and visual loss. In this case series of three affected patients harbouring the m.11778G>A mutation, we provide evidence suggesting that raised intraocular pressure could be a risk factor triggering visual loss in at-risk LHON carriers.

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Clinical Case Notes

Cited by 19 publications

References 7 publications

Respiratory Chain Complex I Deficiency in Leber Hereditary Optic Neuropathy: Insights from Ophthalmologic and Molecular Investigations in Tunisia

Respiratory Chain Complex I Deficiency in Leber Hereditary Optic Neuropathy: Insights from Ophthalmologic and Molecular Investigations in Tunisia

Lateral thinking – Interocular symmetry and asymmetry in neurovascular patterning, in health and disease

Raised Intraocular Pressure as a Potential Risk Factor for Visual Loss in Leber Hereditary Optic Neuropathy

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