Phenotypic heterogeneity of MELAS☆☆☆

With interest we read the article by Dvorakova et al. about 50 Czech patients carrying the m.3243ANG mutation [1]. It raises questions and concerns. Since MELAS is a progressive disease, we should be informed about the long-term follow-up findings in the 50 mutation carriers. How many of the 17 patients without clinical manifestations at inclusion developed MELAS during follow-up? How many of the patients had a family history positive for MELAS, and in how many families were first-degree relatives tested for the m.3243ANG mutation? Altogether, 42% of the patients had seizures [1]. How many of the seizures in these patients occurred prior to a stroke-like episode (SLE), during a SLE, or were unrelated to SLEs? [2] Which were the cardiovascular risk factors among those with ischemic strokes? Was ischemic stroke related to SLE's or independent of it? Which was the cause of rhabdomyolysis in the two reported patients? [1] Was it a previous seizures, alcohol consumption, a drug, or other causes? Did those with rhabdomyolysis also have myopathy? Howmany of thosewith psychiatric disturbances had abnormalities on cerebral MRI or EEG? How many of those with psychiatric disease had SLEs or seizures? Since a number of drugs may be mitochondrion-toxic, in particular antiepileptic drugs (AEDs) (phenytoin, valproate, carbamazepine, phenobarbital), we should be informed how many patients were regularly taking AEDs or other drugs.