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The Spectrum of Maculopathy in Mitochondrial DNA A3243G Mutation: A Case Series of Six Patients
Eirini Kaisari1, François-Xavier Borruat1
1Ophthalmology, Jules Gonin Eye Hospital, Lausanne, Switzerland.
Background:
The mitochondrial DNA (mtDNA) A3243G point mutation encompasses a heterogenous group of disorders including mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), maternally inherited diabetes and deafness (MIDD), and, rarely, chronic progressive external ophthalmoplegia (CPEO). Regardless of the clinical phenotype, a specific retinopathy has been associated with the presence of this mitochondrial DNA mutation. We present six female patients exhibiting retinopathy of the A3243G point mutation at various stages.
History And Signs:
Six female patients (37 - 70 years old) with the A3243G point mutation (four MELAS, one MIDD, and one CPEO) exhibited a maculopathy. Visual acuity ranged from 1/60 to 10/10. Visual field abnormalities varied from minimal decreased sensitivity to absolute central scotomas. They all exhibited, at various degrees, a characteristic pattern of perimacular and peripapillary retinal pigment epithelium (RPE) alterations, with mottled dys-autofluorescence and RPE atrophy and deposits on OCT.
Therapy And Outcome:
The level of visual impairment depended on the foveal involvement and the extension of RPE atrophy. The severity of the maculopathy was not related to age. In the only long-term follow-up (15 years), evolution was slowly progressive.
Conclusions:
A single mtDNA point mutation at locus 3243 can result in a variety of clinical presentations (MELAS, MIDD, or CPEO). Ocular involvement may manifest as a perimacular/peripapillary RPE atrophy/deposit, which can variably impact central visual function (from asymptomatic to legal blindness). The discovery of such a maculopathy should prompt the ophthalmologist to complete the personal and family history, namely, asking for the presence of diabetes mellitus and/or deafness.
Insights
The mitochondrial DNA A3243G mutation can cause various disorders, including a specific retinopathy. This maculopathy presents as retinal pigment epithelium alterations and can impact vision, prompting further patient history for related conditions.
Area of Science:
- Genetics
- Ophthalmology
- Neurology
Background:
- The mitochondrial DNA (mtDNA) A3243G point mutation is associated with diverse clinical disorders such as MELAS, MIDD, and CPEO.
- A distinct retinopathy pattern is consistently observed in individuals with the A3243G mtDNA mutation, irrespective of their primary clinical phenotype.
Purpose of the Study:
- To describe the ocular manifestations, specifically retinopathy, associated with the A3243G mtDNA point mutation in a cohort of female patients.
- To characterize the stages and visual impact of this specific retinopathy.
Main Methods:
- Retrospective analysis of six female patients (ages 37-70) with the A3243G mtDNA mutation (diagnoses included MELAS, MIDD, and CPEO).
- Ophthalmological examination including visual acuity, visual field testing, funduscopy, optical coherence tomography (OCT), and fundus autofluorescence.
- Correlation of ocular findings with mutation type and clinical presentation.
Main Results:
- All six patients presented with a maculopathy characterized by perimacular and peripapillary retinal pigment epithelium (RPE) alterations, including mottled dys-autofluorescence, RPE atrophy, and deposits on OCT.
- Visual acuity ranged from 1/60 to 10/10, with visual field abnormalities varying from decreased sensitivity to central scotomas.
- The degree of visual impairment correlated with foveal involvement and RPE atrophy extent; severity was not age-dependent. Long-term follow-up showed slow progression.
Conclusions:
- The A3243G mtDNA point mutation can manifest with a spectrum of clinical phenotypes, including a characteristic maculopathy.
- Ocular findings of RPE atrophy and deposits can significantly affect central vision, ranging from asymptomatic to legal blindness.
- Ophthalmologists should consider the A3243G mutation in patients with this retinopathy and inquire about personal/family history of diabetes mellitus and deafness.
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