PURPOSE: The disease entity mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is characterized by an early onset of stroke-like episodes. MELAS is the most dominant subtype of mitochondrial disease. Molecular genetic testing is important in the diagnosis of MELAS. The mitochondrial DNA (mtDNA) 3243A>G mutation is found in 80% of MELAS patients. Nevertheless, molecular analysis alone may be insufficient to diagnose MELAS because of mtDNA heteroplasmy. This study aimed to evaluate whether muscle biopsy is useful in MELAS patients as an initial diagnostic evaluation method. MATERIALS AND METHODS: The medical records of patients who were diagnosed with MELAS at the Department of Pediatrics of Gangnam Severance Hospital between January 2006 and January 2017 were reviewed. The study population included 12 patients. They were divided into two subgroups according to whether the results of muscle pathology were in accordance with mitochondrial diseases. Clinical variables, diagnostic evaluations, and clinical outcomes were compared between the two groups. RESULTS: Of the 12 patients, seven were muscle pathology-positive for mitochondrial disease. No statistically significant difference in clinical data was observed between the groups that were muscle pathology-positive and muscle pathology-negative for mtDNA 3243A>G mutation. Additionally, the patients with weakness as the initial symptom were all muscle pathology-positive. CONCLUSION: The usefulness of muscle biopsy appears to be limited to an initial confirmative diagnostic evaluation of MELAS. Muscle biopsy can provide some information in MELAS patients with weakness not confirmed by genetic testing.
Biopsy* ; Diagnosis ; DNA, Mitochondrial ; Genetic Testing ; Humans ; Medical Records ; MELAS Syndrome* ; Methods ; Mitochondrial Diseases ; Mitochondrial Encephalomyopathies* ; Molecular Biology ; Pathology ; Pediatrics

Taurine is an abundant, β-amino acid with diverse cytoprotective activity. In some species, taurine is an essential nutrient but in man it is considered a semi-essential nutrient, although cells lacking taurine show major pathology. These findings have spurred interest in the potential use of taurine as a therapeutic agent. The discovery that taurine is an effective therapy against congestive heart failure led to the study of taurine as a therapeutic agent against other disease conditions. Today, taurine has been approved for the treatment of congestive heart failure in Japan and shows promise in the treatment of several other diseases. The present review summarizes studies supporting a role of taurine in the treatment of diseases of muscle, the central nervous system, and the cardiovascular system. In addition, taurine is extremely effective in the treatment of the mitochondrial disease, mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and offers a new approach for the treatment of metabolic diseases, such as diabetes, and inflammatory diseases, such as arthritis. The review also addresses the functions of taurine (regulation of antioxidation, energy metabolism, gene expression, ER stress, neuromodulation, quality control and calcium homeostasis) underlying these therapeutic actions.
Acidosis, Lactic ; Arthritis ; Brain Diseases ; Calcium ; Cardiovascular System ; Central Nervous System ; Cytoprotection ; Energy Metabolism ; Gene Expression ; Heart Failure ; Japan ; MELAS Syndrome ; Metabolic Diseases ; Mitochondrial Diseases ; Neurodegenerative Diseases ; Pathology ; Quality Control ; Taurine*

Adult ; Dandy-Walker Syndrome ; complications ; pathology ; Humans ; MELAS Syndrome ; complications ; pathology ; Magnetic Resonance Imaging ; Male

OBJECTIVETo delineate the characteristics of the clinical manifestation, pathology of skeletal muscle and gene mutations of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode (MELAS) in children.

METHODThe clinical manifestation, laboratorial data, brain images, muscle pathology and mitochondrial gene mutations were analyzed in 24 patients with MELAS who were diagnosed in Department of Pediatrics, Peking University First Hospital. Their prognosis was evaluated by following up.

RESULTSymptoms of central nervous system such as stroke-like episodes, vomiting, convulsion and headache were present in all the 24 cases. Nine cases had the symptoms of myopathy. Twenty cases had developmental delay. Short stature, being thin and hairy was very common in these cases. Serum lactate level increased in all the cases, pyruvate increased in 17 cases. Elevated CSF lactate was found in 2 cases. Magnetic resonance imaging (MRI) was performed on 24 cases, out of them 23 were abnormal. The lesions mainly involved cerebral lobes. Occipital lobe was the most common site of lesions. Computed tomography (CT) was performed on 13 cases, low density lesions were present in 10 cases, basal ganglia calcifications in 5 cases. Muscle biopsy was performed on 8 cases, ragged-red fibers (RRF) were found in 4/8 cases, and abnormal accumulation of mitochondria were found in 3/8 cases. The mtDNA gene mutational analysis showed A3243G mutation in these patients. The mutation rates varied from 11.6% to 75.0%. The same mutation were found in 4/5 mothers who had the genetic tests, and the mutation rates of the mothers varied from 15.0% to 23.6%. The clinical information of 11 cases was available through recent following up. Three cases died, the others had some degrees of mental retardation.

CONCLUSIONChildren with MELAS had various clinical manifestations. Central nervous system and skeletal muscle were usually involved. Short stature and hypertrichosis were common signs. The prognosis of this disease was disappointing. mtDNA A3243G was the most common mutation in MELAS. Fully understanding the characteristics of its clinical manifestation, laboratory tests, brain image, muscle pathology and molecular features can be helpful to the early diagnosis and treatment.

Acidosis, Lactic ; blood ; Adolescent ; Brain ; diagnostic imaging ; pathology ; Child ; Child, Preschool ; DNA Mutational Analysis ; DNA, Mitochondrial ; genetics ; Electroencephalography ; Female ; Follow-Up Studies ; Humans ; Infant ; MELAS Syndrome ; diagnosis ; genetics ; pathology ; Magnetic Resonance Imaging ; Male ; Muscle, Skeletal ; diagnostic imaging ; pathology ; Point Mutation ; Pyruvic Acid ; blood ; Stroke ; diagnostic imaging ; genetics ; pathology ; Syndrome ; Tomography, X-Ray Computed

OBJECTIVE: We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. MATERIALS AND METHODS: We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. RESULTS: Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 +/- 40.9% in the MELAS and 64 +/- 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. CONCLUSION: The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage.
Adolescent ; Adult ; Brain/*pathology ; Brain Edema/pathology ; Child ; *Diffusion Magnetic Resonance Imaging ; Female ; Humans ; MELAS Syndrome/*pathology ; *Magnetic Resonance Angiography ; Male ; Middle Aged ; Stroke/pathology ; Young Adult

This study was conducted to investigate the etiology, the clinical characteristics and prognosis of acute necrotizing encephalopathy (ANE) in Korean children. Six children (1 yr to 7 yr) patients with ANE were enrolled. They were diagnosed by clinical and radiological characteristics and their clinical data were retrospectively analyzed. In a search of clinically plausible causes, brain MRI in all patients, mitochondrial DNA studies for mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) and myoclonus epilepsy and ragged red fibers (MERRF) in four patients, and genomic typing on HLA DRB/HLA DQB genes in three patients were performed. All had precedent illnesses and the main initial symptoms included mental change (83%), seizures (50%), and focal deficits (50%). MRI revealed increased T2 signal density in the bilateral thalami and/or the brainstem in all patients. Mitochodrial DNA studies for MELAS and MERRF were negative in those children and HLA-DRB1*1401, HLA-DRB3*0202, and HLA-DQB1*0502 seemed to be significant. A high dose steroid was given to all patients, which seemed to be partly effective except for 2 patients. In conclusion, ANE is relatively rare, but can result in serious neurological complication in children. Early detection and appropriate treatment may lead to a better neurological outcome.
Child ; Child, Preschool ; Female ; HLA-DQ Antigens/metabolism ; HLA-DQ beta-Chains ; HLA-DR Antigens/metabolism ; HLA-DRB1 Chains ; HLA-DRB3 Chains ; Humans ; Infant ; Korea ; Leukoencephalitis, Acute Hemorrhagic/diagnosis/etiology/*pathology/*physiopathology ; MELAS Syndrome/pathology/physiopathology ; MERRF Syndrome/pathology/physiopathology ; Magnetic Resonance Imaging ; Male ; Prognosis ; Retrospective Studies

OBJECTIVETo study the characteristics of spectra on proton magnetic resonance spectroscopy (1H-MRS) and its value in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS).

METHODSSeven clinically diagnosed patients with MELAS underwent magnetic resonance imaging (MRI) and 1H-MRS examinations. The 1H-MRS techniques, characteristics of the spectra, and its correlation with the laboratory tests were analyzed.

RESULTSCerebral abnormalities were revealed in all 7 patients on conventional MR images, and most abnormal signals were observed in bilateral occipital, parietal, and temporal lobes. We found 4 cases with basal ganglia involvement, 2 cases with mild frontal lobe lesions, and 1 case with involvement of lateral cerebral peduncles and thalami. Additionally, 1 patient was involved with left insular lobe. Spectra from prominent lesions in brain parenchyma showed lactate doublet peak in 6 patients, 3 of whom were also noted lactate peak in ventricular cerebrospinal fluid (CSF).

CONCLUSION1H-MRS may provide more direct information about the metabolism changes, which aids to affirm the diagnosis, and may replace the conventional invasive method of quantifying lactate in CSF.

Adolescent ; Adult ; Basal Ganglia ; pathology ; physiopathology ; Cerebral Cortex ; pathology ; physiopathology ; Child ; Female ; Humans ; Lactic Acid ; metabolism ; MELAS Syndrome ; diagnosis ; physiopathology ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Male ; Parietal Lobe ; pathology ; physiopathology

Adolescent ; Adult ; Child ; Humans ; MELAS Syndrome ; diagnosis ; pathology ; Magnetic Resonance Imaging ; Male ; Tomography, X-Ray Computed

Adult ; DNA, Mitochondrial ; genetics ; Female ; Humans ; MELAS Syndrome ; genetics ; pathology ; Male ; Middle Aged ; Muscles ; pathology ; Mutation

Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episode (MELAS) and myoclonic epilepsy and raggedred fibers (MERRF) are rare disorders caused by point mutation of the tRNA gene of the mitochondrial genome. To understand the pathogenetic mechanism of MELAS and MERRF, we studied four patients. Serially sectioned frozen muscle specimens with a battery of histochemical stains were reviewed under light microscope and ultrastructural changes were observed under electron microscope. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed and the tRNA genes were sequenced to confirm mutations. In two patients with MELAS, strongly succinyl dehydrogenase positive blood vessels (SSVs) and many cytochrome oxidase (COX) positive raggedred fibers (RRFs) were observed, and A3243G mutations were found from the muscle samples. In two patients with MERRF, neither SSV nor COX positive RRFs were seen and A8344G mutations were found from both muscle and blood samples. In the two MERRF families, the identical mutation was observed among family members. The failure to detect the mutation in blood samples of the MELAS suggests a low mutant load in blood cells. The histochemical methods including COX stain are useful for the confirmation and differentiation of mitochondrial diseases. Also, molecular biological study using muscle sample seems essential for the confirmation of the mtDNA mutation.
Adolescent ; Adult ; Electron Transport Complex IV/metabolism ; Female ; Humans ; Korea ; MELAS Syndrome/*genetics/metabolism/*pathology ; MERRF Syndrome/*genetics/metabolism/*pathology ; Male ; Pedigree ; Polymerase Chain Reaction/methods ; Polymorphism, Restriction Fragment Length ; RNA, Transfer ; Sequence Analysis, DNA