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Cardiac manifestations of mitochondrial disorders.

Year: 2013
Type: article
Abstract: To the Editor: With interest, we read the review about mitochondrial cardiomyopathy by Meyers and colleagues.1 We have the following comments and concerns. The authors provided a comprehensive overview of the cardiac manifestations of mitochondrial disorders. In addition to the cardiac abnormalities listed in their Table I, pulmonary artery hypertension should be mentioned. It can occur as an isolated phenotypic feature in nonsyndromic and syndromic mitochondrial disorders.2 Two syndromic disorders that manifest themselves with pulmonary artery hypertension are HUPRA syndrome (hyperuricemia, pulmonary hypertension, renal failure in infancy, and alkalosis), caused by mutations in SARS2, which encodes the mitochondrial seryl-tRNA synthetase2; and MELAS syndrome (mitochondrial encephalopathy with lactic acidosis and stroke-like episodes), caused by mutations in the tRNALeu gene. In nonsyndromic disorders, pulmonary artery hypertension has been described in association with mutations in the NFU1, tRNAGlu, and COX7B genes.3 Another cardiac abnormality occasionally associated with mitochondrial disorders is arterial hypertension.4 Arterial hypertension, described in syndromic and nonsyndromic mitochondrial conditions, can be caused by mutations in mitochondrial DNA (mtDNA) or nuclear DNA (nDNA)-located genes.4 Maternal arterial hypertension has been associated with the cytochrome b 15059G>A mtDNA mutation4 and the ribosomal RNA 1555A>G mutation. Arterial hypertension has also been found in those who carry SLC25A4 or SDHD mutations. A rare cardiac manifestation of mitochondrial disease is a patent foramen ovale. It has been found in patients with MELAS syndrome and in those who carry mutations in the DNA2 or BSCL2 genes.5 Patients with mtDNA depletion syndrome or tRNALeu mutations can also develop ventricular septal defects. A further point that we want to mention is that cardiomyopathy in mitochondrial disorders occurs not only in syndromic conditions but also in the nonsyndromic forms, and much more frequently. Nonsyndromic disorders often go undetected for years, because of their nonspecific clinical manifestations and slow progression. Only when patients develop acute cardiac symptoms might they undergo thorough investigations that reveal the underlying defect. Finally, there is no evidence that coenzyme Q, L-carnitine, creatine phosphate, thiamine, riboflavin, vitamin C, vitamin E, idebeneone, or dihydrolipoate is therapeutically beneficial for cardiac manifestations of mitochondrial disorders, and heart transplantation must be mentioned as a treatment for intractable heart failure caused by mitochondrial dilative cardiomyopathy. Heart transplantation has been successfully performed in patients carrying tRNAIle mutations6 and in mtDNA depletion syndrome. Overall, mitochondrial cardiac disease is even more variable than described. Despite the absence of causal treatments, effective symptomatic measures should be applied, particularly for mitochondrial cardiomyopathy. Josef Finsterer, MD, PhD Krankenanstalt Rudolfstiftung, Vienna, Austria Sinda Zarrouk-Mahjoub, PhD Laboratory of Biochemistry, UR “Human Nutrition and Metabolic Disorders,” Faculty of Medicine, Monastir, Tunisia
Language: English
Open Access status: green
OpenAlex ID: W2277975923
FWCI:
Cites: 5
Cited by: 2
Related to: 10