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| LETTER TO EDITOR |
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| Year : 2023 | Volume
: 22
| Issue : 3 | Page : 402-403 |
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Cerebral magnetic resonance imaging lesions in leigh syndrome are variegated
Josef Finsterer
Neurology and Neurophysiology Center, Vienna, Austria
| Date of Submission | 28-Nov-2022 |
| Date of Decision | 04-Mar-2023 |
| Date of Acceptance | 20-Mar-2023 |
| Date of Web Publication | 4-Jul-2023 |
Correspondence Address:
Josef Finsterer
Postfach 20, 1180 Vienna
Austria
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/aam.aam_166_22
How to cite this article:
Finsterer J. Cerebral magnetic resonance imaging lesions in leigh syndrome are variegated. Ann Afr Med 2023;22:402-3 |
Sir,
We read with interest the article by Kakkar et al. about a retrospective study of the cerebral magnetic resonance imaging (MRI) findings in eight patients with Leigh syndrome.[1] It was found that all patients had brainstem involvement, 62.5% had basal ganglia involvement, 37.5% had white matter lesions, 25% had cerebellar involvement, and one each spinal cord, thalamus, and corpus callosum involvement.[1] It was concluded that conventional MRI serves as an excellent tool for the diagnosis of pediatric Leigh syndrome, acute encephalopathy commonly presents with diffusion restriction corresponding to active lesions, and diffusion restriction predicts the activity of cerebral lesions in Leigh syndrome.[1] The study is appealing but raises concerns that warrant further discussion.
The main limitation of the study is that the diagnosis of Leigh syndrome was not genetically confirmed in any of the included patients.[1] Knowing the genetic defect is crucial as mitochondrial disorders are characterized by genetic and phenotypic heterogeneity. Particularly, Leigh syndrome is genetically heterogeneous.[2] Mutations in more than 75 genes have been shown to cause Leigh syndrome.[2] Similarly, type, extension, and dynamics of MRI findings may strongly depend on the underlying genetic defect. MRI findings may be specific for certain genetic defects. To extract typical patterns of MRI findings, associated with a specific mutation, it is essential to know the causative genetic variant.
Patient-8 had hyperintensity on diffusion weighted imaging and hyperintensity on apparent diffusion coefficient maps, suggesting that there was no cytotoxic edema but a vasogenic edema. We should be informed about the interpretation of this unusual finding.
The diagnostic criteria applied requested that patients had bilaterally symmetric basal ganglia lesions.[1] However, only 5/8 patients had basal ganglia lesions.[1] We should know if the three patients without basal ganglia lesions (patients 1, 4, and 5) had symmetric brainstem lesions or not.
An MRI lesion not discussed in the article is the stroke-like lesion (SLL), which is the morphological correlate of a stroke-like episode (SLE).[3] SLLs have been particularly reported in patients with overlaps between Leigh syndrome and mitochondrial encephalopathy, lactic acidosis, and stroke-like episode syndrome.[4] We should know if any of the eight included patients had a history of SLEs.
Another lesion type not assessed or discussed is intracerebral calcification. Intracerebral calcifications most commonly concern the basal ganglia but can occur in other cerebral locations as well.[5] Calcifications are most commonly due to endocrine involvement in Leigh syndrome, particularly hypoparathyroidism. There is also no discussion of cerebral atrophy or the Panda sign.[5]
Because patients with Leigh syndrome can also manifest with endocrine abnormalities including pituitary adenoma or empty sella,[5] we should know how many of the patients had abnormal signals within the sella or pituitary gland.
We disagree with the statement that diffusion restriction predicts the activity of cerebral lesions in Leigh syndrome. Diffusion restriction can also be a postictal phenomenon, when the epileptic activity is already over.
Overall, the study carries obvious limitations that require re-evaluation and discussion. Clarifying these weaknesses would strengthen the conclusions and could improve the study.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
 References | |  |
| 1. | Kakkar C, Gupta S, Kakkar S, Gupta K, Saggar K. Spectrum of magnetic resonance abnormalities in Leigh syndrome with emphasis on correlation of diffusion-weighted imaging findings with clinical presentation. Ann Afr Med 2022;21:426-31.  [Full text] |
| 2. | Bakare AB, Lesnefsky EJ, Iyer S. Leigh syndrome: A tale of two genomes. Front Physiol 2021;12:693734. |
| 3. | Finsterer J, Aliyev R. Metabolic stroke or stroke-like lesion: Peculiarities of a phenomenon. J Neurol Sci 2020;412:116726. |
| 4. | Wei Y, Huang Y, Yang Y, Qian M. MELAS/LS overlap syndrome associated with mitochondrial DNA mutations: Clinical, genetic, and radiological studies. Front Neurol 2021;12:648740. |
| 5. | Newstead SM, Finsterer J. Leigh-like syndrome with a novel, complex phenotype due to m. 10191T>C in Mt-ND3. Cureus 2022;14:e28986. |
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