Familial mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episode syndrome:Three case reports

BACKGROUND Mitochondrial encephalomyopathy(ME)is a multisystem metabolic disease that primarily affects the central nervous system and skeletal muscle.It is caused by mutations in mitochondrial or nuclear DNA,resulting in abnormal mitochondrial structure and function and insufficient ATP synthesis.The most common subtype is mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episode(MELAS)syndrome.In recent years,reports of MELAS syndrome have increased but familial cases are rare.CASE SUMMARY We report a case of familial MELAS syndrome.Cases 2 and 3 are sisters and case 1 is their nephew.All are short in stature and showed stroke-like episodes with rapid onset and no obvious symptoms such as paroxysmal headache,aphasia,or blurred vision.After admission,blood lactate levels were significantly higher than normal.The patients underwent magnetic resonance imaging of the head.Cases 1 and 2 were considered to have ME,whereas case 3 was considered to have a space-occupying lesion in the left temporal lobe.Pathological evaluation showed no obvious tumor cells in the brain lesions of case 3.Muscle biopsy or genetic test results were consistent with ME.The patients were diagnosed with MELAS syndrome and their symptoms improved with intravenous infusions of coenzyme Q10,coenzyme A,vitamin B,and vitamin C.At the 6 mo follow-up,there was no recurrence or progression.CONCLUSION When a patient has MELAS syndrome,familial MELAS syndrome should be considered if related family members have similar symptoms.

White matter connection's damage,not cortical activation, leading to language dysfunction of mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes

Mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes (MELAS) is a metabolic disorder characterized by hyperlactic acidemia and stroke-like symptoms.

Mortality in mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episodes does not depend on levetirazetam alone

We appreciated reading the article by Zhang et al[1] about a retrospective study of 102 mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) patients with epilepsy in which disability and outcome were assessed (median follow-up: 4 years). Administration of levetirazetam (LEV) was associated with a better outcome compared to other antiepileptic drugs (AEDs).[1] The study has several shortcomings requiring discussion.

Clinical,pathological and genetic study of a kindred of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes

The first description of a syndrome including stroke-like episodes, lactic acidaemia, and ragged red fibres, was reported by Shapira et al in 1975. 1 Pavlakis et al 2 described further cases, introduced the acronym MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes), and suggested that this represented a distinct mitochondrial disease phenotype. In 1990, Goto et al 3 identified A3243G mutation in the transfer RNA (tRNA) leucine (UUR) gene in some patients with MELAS. Although this mutation has now been established to be the commonest mtDNA defect it is often misdiagnosed. Here we report a kindred of MELAS including a mother and a son. Clinical, pathological and genetic studies are proceeding.

Myopathological features in MELAS syndrome without significant changes in muscle biopsy pathology

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes （MELAS） are common types of mitochondrial encephalomyopathy. The involved muscular pathology is characterized by typical changes of mitochondrial abnormalities. Gene screening has been the gold diagnostic standard for MELAS diagnosis. This study presents three primary MELAS patients, with an age of onset from 13 to 18 years, including one patient with seizure, and two with headache and vomiting. All patients had a family history of disease, with maternal inheritance. Cerebral magnetic resonance imaging revealed abnormally high signals in T2-weighted images： temporal lobe in three cases, occipital lobe in two cases, and parietal lobe in one case. Migrating stroke-like lesions were confirmed in one patient. Muscle biopsy revealed several strongly succinate dehydrogenase-reactive vessels scattered in muscle sections of three patients, but ragged-red fibers and cytochrome c oxidase-negative/dense （COX-/＋） fibers were not observed. Mitochondrial DNA A3243G mutation was identified in all three cases. MELAS syndrome has obvious clinical heterogeneity, and muscle weakness was not prominent in some of the cases. Muscle pathological changes did not accompany ragged-red fibers or COX-/＋ fibers, but succinate dehydrogenase- reactive vessels are important for MELAS diagnosis.

Late-onset mitochondrial disease in a patient with MELAS and mitochondrial DNA T14487C mutation

To the Editor: Mitochondrial encephalomyopathy with lactate acidosis and stroke-like episodes (MELAS) is one of the most common multisystem mitochondrial disorders with broad clinical manifestations.[1] It is usually caused by point mutations in the mitochondrial MT-TL1 gene, which accounts for approximately 80% of mutations in individuals with MELAS syndrome.[2] Pathogenic mitochondrial DNA (mtDNA) mutations were first described in 1980[3] and m.l4487T>C is a known pathogenic mtDNA mutation,[4] which has been reported in patients with Leigh syndrome, optic neuropathy, ptosis, dystonia, and encephalomyopathy. We herein report a patient with late-onset MELAS syndrome with the m.l4487T>C mutation for the first time.