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Kidney involvement in MELAS syndrome: Description of 2 cases
Pau Alcubilla-Prats1, Manel Solé2, Albert Botey1
1Servei de Nefrologia i Trasplantament Renal, Hospital Clínic, Universidad de Barcelona, Barcelona, España.
Introduction:
MELAS syndrome -myopathy, encephalopathy, lactic acidosis and stroke-like episodes- is a maternally-inherited mitochondrial cytopathy related to several mitochondrial DNA mutations, with the A3243G mutation in tRNALeu gene being the most frequent of them.
Patients And Methods:
Apart from its typical symptomatology, patients usually exhibit a maternally-inherited history of neurosensory deafness and insulin-dependent type 2 diabetes mellitus (T2DM). Recent studies have shown that few patients carrying a A3243G mutation also suffer from renal dysfunction, usually in form of focal segmental glomerulosclerosis (FSGS).
Results:
In this study we examine kidney involvement in 2 unrelated patients with a A3243G mutation by genetic testing. Both have a maternally-inherited neurosensory deafness and insulin-dependent T2DM. A renal biopsy was performed in both patients. One patient developed nephrotic proteinuria and renal insufficiency, with FSGS findings being observed in the kidney biopsy, whereas the other suffered from mild proteinuria and renal insufficiency, with non-specific glomerular changes.
Conclusion:
The presence of FSGS or other kidney involvement accompanied by hereditary neurosensory deafness and T2DM could be suggestive of a A3243G tRNALeu mutation and should prompt a genetic testing and an evaluation of potential extrarenal involvement.
Insights
MELAS syndrome, linked to the A3243G mutation, can cause kidney problems like focal segmental glomerulosclerosis (FSGS). Early genetic testing is crucial for patients with deafness and diabetes.
Area of Science:
- Mitochondrial genetics
- Nephrology
- Endocrinology
Background:
- MELAS syndrome is a mitochondrial DNA disorder characterized by myopathy, encephalopathy, lactic acidosis, and stroke-like episodes.
- The A3243G mutation in the tRNALeu gene is the most common cause of MELAS syndrome.
- Patients often present with maternally inherited neurosensory deafness and type 2 diabetes mellitus (T2DM).
Observation:
- This study investigated renal involvement in two unrelated patients with the A3243G mutation.
- Both patients had a history of maternally inherited neurosensory deafness and insulin-dependent T2DM.
- Renal biopsies were performed to assess kidney pathology.
Findings:
- One patient developed nephrotic proteinuria and renal insufficiency, with kidney biopsy showing focal segmental glomerulosclerosis (FSGS).
- The second patient exhibited mild proteinuria and renal insufficiency with non-specific glomerular changes.
- These findings highlight variable renal manifestations in A3243G mutation carriers.
Implications:
- The co-occurrence of FSGS, neurosensory deafness, and T2DM may indicate an underlying A3243G mutation.
- Genetic testing for the A3243G mutation is recommended in such cases.
- Evaluation for extrarenal complications is important in patients with MELAS syndrome and renal involvement.
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