Pancreatitis in mitochondrial disorders

Dear Editor, with interest we read the article by Zhiping et al. about 5 patients from a Chinese family with MELAS due to the m.3243A>G mutation of whom 2 also had pancreatitis in the absence of a PRSS1 mutation [1]. We have the following comments and concerns.
We do not agree with the statement that only six patients carrying an mtDNA mutation have been so far reported with pancreatitis (Table I) [1]. Pancreatitis was reported in at least 16 other MID patients (Table I) [2]. Interestingly, pancreatitis has not been reported in association with mutations in nDNA located genes. Among MID patients carrying the mtDNA mutation m.3243A>G pancreatitis has been reported in at least 8 patients (Table I).
In the abstract it is stated that 7 members of the family carried the m.3243A>G mutation. However, in the clinical data section, only 5 patients are presented. We should be informed about the reason why 2 patients were excluded from the study. A further discrepancy derives from Figure 1 which shows 9 affected patients. What was the reason why 4 pa­tients were excluded? Another inconsistency concerns the PRSS1 mutation. In the abstract it is mentioned that it was found in all tissue samples of all 5 included patients. However, in the results section it is mentioned that no mutations were found in the PRSS1, SPINK1, and CFTR genes [1].
Proband I/2 is indicated as deceased in Figure 1 [1]. How can this subject have been investigated if he is dead?
The authors mention that they also recorded EEGs of all included patients [1]. How many of the 5 included patients and the 9 clinically affected had epilepsy? What types of seizures were reported, which antiepileptic drugs were administered, and what was the quality of the seizure control? Particularly patient III/1 had epilepsy. Was she put on a ketogenic diet, which has been shown beneficial at least in some patients with mitochondrial epilepsy [3]?
The authors mention that a structured questionnaire was applied but no results are reported [1]. What was the purpose of applying such a questionnaire and what were the results and their interpretation?
It is quite unusual to find the same abnormality in all 5 included patients in the light of the variable heteroplasmy rates [1]. Did truly all 5 patients show up with cytotoxic edema in the internal capsule bilaterally as presented in the results?
Since MELAS is characterised by the occurrence of stroke-like episodes (SLEs) it would be...


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