Evaluation of a mitochondrial disease criteria scoring system on mitochondrial encephalomyopathy in Chinese patients.

Due to the complicated clinical features of mitochondrial encephalomyopathy, simplified mitochondrial disease criteria (MDC) have recently been established in Europe. This study evaluated the sensitivity and specificity of this scoring system in Chinese patients. Seventy-eight patients with suspected mitochondrial encephalomyopathy were recruited to be scored by the simplified MDC and were further classified into "possible" (2-4), "probable" (5-7), or "definite" categories (≥8). Significant differences were observed between the total scores in the mitochondrial encephalomyopathy group and the other myopathy group. In the mitochondrial encephalomyopathy group, 73.5% of patients had a score above 8, whereas in the other myopathy group, the "definite" percentage was only 3.2%, suggesting the proposed MDC scoring system has a high sensitivity for diagnosis of mitochondrial encephalomyopathy in China. Moreover, there were significant differences in the clinical scores and imaging portions of the MDC, suggesting that the simplified MDC may distinguish mitochondrial disorder from other multisystem disorders to aid in early diagnosis prior to a muscle biopsy.