MELAS

From Ganfyd

See mitochondrial diseases for more details of the context of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes a mitochondrial disorder with usual onset (in 90%) before 40 years. It is associated with seizures, headaches, vomiting attacks and diabetes mellitus. It results in dementia. Normal lactate and/or pyruvate levels effectively exclude it, although there are reports of variable penetrance, and raised CSF lactate is more specific at the time of stroke like episodes.

Aetiology

Multiple point mutations can cause it in the MT-TL1 (TRNL1, MTTL1, tRNA^Leu(UUR), mitochondrially encoded tRNA leucine 1 (UUA/G)) , MT-TQ (TRNQ, MTTQ, tRNA^Glu mitochondrially encoded tRNA glutamine), MT-TH (TRNH, MTTH, tRNA^His, mitochondrially encoded tRNA histidine), MT-TK (TRNK, MTTK, tRNA^Lys, mitochondrially encoded tRNA lysine), MT-TS1 (TRNS1, MTTS1, tRNA^Ser mitochondrially encoded tRNA serine 1 (UCN)), MT-ND1 (MTND1, mitochondrially encoded NADH dehydrogenase 1), MT-ND5 (ND5, MTND5, mitochondrially encoded NADH dehydrogenase 5), MT-COI (COX1, mitochondrially encoded cytochrome c oxidase I)^[1] or MT-ND6 (ND6, mitochondrially encoded NADH dehydrogenase 6) genes. The most common mutation is A3243G in the MT-TL1 gene^[2].

Treatment

There is no proven treatment. In particular dichloroacetate (DCA) has been shown in two trials to cause in due course neuropathic symptoms that appear to outweigh any benefit. The status of arginine and coenzyme Q10 are unknown^[3].

References