Related Experiment Videos
Retinal dystrophy in a Japanese boy harboring the mitochondrial DNA T8993G mutation
Tetsuya Yamada1, Seiji Hayasaka, Kazuhisa Hongo
1Departments of Ophthalmology, Toyama, Japan.
Background:
Patients with the mitochondrial (mt) DNA T8993G mutation reportedly have variable neurologic manifestations. In these patients, retinal dystrophies progress from salt-and-pepper appearance to severe diffuse pigmentary retinopathy.
Case:
A Japanese boy harboring the mtDNA T8993G mutation had hypotonia, ataxia, and developmental delay. His lactate values in serum and cerebrospinal fluid were elevated. Magnetic resonance imaging showed symmetrical areas of T2-weighted hyperintensity in the putamen and caudate.
Observations:
In ophthalmological examinations, his pupils reacted sluggishly to light. The patient had mottling of the retina without pigmentation and subnormal electroretinographic responses in both fundi. No ophthalmoparesis or nystagmus was observed.
Conclusion:
Retinal dystrophy without pigmentation was found in a Japanese boy diagnosed with the mtDNA T8993G mutation. This is believed to be the first report of retinal manifestations in Japanese patients with this mutation.
Insights
Mitochondrial DNA T8993G mutation causes variable neurological issues. A Japanese boy showed retinal dystrophy without pigmentation, a rare manifestation of this mutation.
Area of Science:
- Genetics
- Neurology
- Ophthalmology
Background:
- Mitochondrial (mt) DNA T8993G mutation is linked to diverse neurological symptoms.
- Retinal dystrophies in affected patients typically progress from mild to severe pigmentary changes.
Observation:
- A Japanese boy with the T8993G mutation presented with hypotonia, ataxia, and developmental delay.
- Elevated lactate levels were detected in his serum and cerebrospinal fluid.
- MRI revealed symmetrical T2-weighted hyperintensities in the putamen and caudate nuclei.
Findings:
- Ophthalmological examination showed sluggish pupillary responses and retinal mottling without distinct pigmentation.
- Electroretinography revealed subnormal responses in both fundi.
- No ophthalmoparesis or nystagmus was observed in this patient.
Implications:
- This case highlights retinal dystrophy without pigmentation as a potential manifestation of the mtDNA T8993G mutation.
- This is the first reported instance of such retinal findings in a Japanese patient with this specific mitochondrial DNA mutation.