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

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a maternally inherited mitochondrial disorder of which m.3243A>G is the most commonly associated mutation, resulting in an inability to meet the energy requirements of various organs. MELAS poses a diagnostic challenge owing to its multiple organ involvement and great clinical variability due to its heteroplasmic nature. We report three cases from a family who were initially misdiagnosed with myasthenia gravis or undiagnosed. Although there is no optimal consensus treatment approach for patients with MELAS because of the disease's heterogeneity, our 21-year-long therapy regimen of l-arginine, l-carnitine, and coenzyme Q10 supplementation combined with dietary management appeared to provide noticeable protection from the symptoms and complications. Prompt early diagnosis is important, as optimal multidisciplinary management and early intervention may improve outcomes.
Acidosis, Lactic ; Arginine ; Carnitine ; Consensus ; DNA, Mitochondrial ; Early Diagnosis ; Early Intervention (Education) ; Follow-Up Studies ; Humans ; MELAS Syndrome ; Mitochondrial Diseases ; Myasthenia Gravis ; Population Characteristics

DNA, Mitochondrial ; genetics ; Humans ; MELAS Syndrome ; diagnosis ; diagnostic imaging ; genetics ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Mutation ; genetics

PURPOSE: Leber hereditary optic neuropathy (LHON) is one of the most common hereditary optic neuropathies caused by mutations of mitochondrial DNA. Three common mitochondrial mutations causing LHON are m.3460, m.11778, and m.14484. We report a rare mutation of the mitochondrial tRNA (Leu [UUR]) gene (MT-TL1) (m.3268 A > G) in a patient with bilateral optic atrophy. CASE SUMMARY: A 59-year-old female diagnosed with glaucoma 3 years earlier at a community eye clinic presented to our neuro-ophthalmology clinic. On examination, her best corrected visual acuity was 0.4 in the right eye and 0.7 in the left eye, and optic atrophy was noticed in both eyes. Optical coherence tomography revealed retinal nerve fiber layer (RNFL) thinning in both eyes; average RNFL thickness was 52 µm in the right eye and 44 µm in the left eye, but the papillomacular bundle was relatively preserved in both eyes. Goldmann perimetry demonstrated peripheral visual field defects, mostly involving superotemporal visual field in both eyes. Mitochondrial DNA mutation test showed an unusual mutation in MT-TL1 gene seemingly related to this optic neuropathy. CONCLUSIONS: We found a rare mutation (m.3268 A > G) of the mitochondrial DNA in a patient having bilateral optic atrophy, which led to the diagnosis of LHON. There have been previous reports about mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) and infantile myopathy caused by MT-TL1 mutation, but this is the first case of LHON associated with the same mutation. In this case of LHON associated with MT-TL1 mutation, atypical clinical features were observed with a relatively mild phenotype and peripheral visual field defects.
Diagnosis ; DNA, Mitochondrial ; Female ; Glaucoma* ; Humans ; MELAS Syndrome ; Middle Aged ; Muscular Diseases ; Nerve Fibers ; Optic Atrophy ; Optic Atrophy, Hereditary, Leber* ; Optic Nerve Diseases ; Phenotype ; Retinaldehyde ; RNA, Transfer ; Tomography, Optical Coherence ; Visual Acuity ; Visual Field Tests ; Visual Fields

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome presents with various clinical features, including seizures, stroke-like episodes, encephalopathy, myopathy, cardiac involvement, and diabetes. However, due to its clinical heterogeneity, the diagnosis of MELAS syndrome is complex and difficult. The present report describes an 18-year-old male who was diagnosed with MELAS syndrome following the onset of type 1 diabetes. The patient had suffered from ataxia, mental retardation, and recurrent headaches for several years; following hospitalization for loss of consciousness, he was treated for cerebellar atrophy and Wolf-Parkinson-White (WPW) syndrome. Although the patient had no history of lactic acidosis, the recent onset of type 1 diabetes and his medical history of encephalopathy and WPW syndrome suggested MELAS syndrome. The diagnosis of MELAS syndrome was confirmed by molecular genetic testing, which revealed a point mutation (A3243G) in the patient's mitochondrial DNA.
Acidosis, Lactic ; Adolescent ; Ataxia ; Atrophy ; Diabetes Mellitus, Type 1* ; Diagnosis ; DNA, Mitochondrial ; Headache ; Hospitalization ; Humans ; Intellectual Disability ; Male ; MELAS Syndrome* ; Molecular Biology ; Muscular Diseases ; Point Mutation ; Population Characteristics ; Seizures ; Unconsciousness ; Wolff-Parkinson-White Syndrome

OBJECTIVEMitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a progressive, multisystem affected mitochondrial disease associated with a number of disease-related defective genes. MELAS has unpredictable presentations and clinical course, and it can be commonly misdiagnosed as encephalitis, cerebral infarction, or brain neoplasms. This review aimed to update the diagnosis progress in MELAS, which may provide better understanding of the disease nature and help make the right diagnosis as well.

DATA SOURCESThe data used in this review came from published peer review articles from October 1984 to October 2014, which were obtained from PubMed. The search term is "MELAS".

STUDY SELECTIONInformation selected from those reported studies is mainly based on the progress on clinical features, blood biochemistry, neuroimaging, muscle biopsy, and genetics in diagnosing MELAS.

RESULTSMELAS has a wide heterogeneity in genetics and clinical manifestations. The relationship between mutations and phenotypes remains unclear. Advanced serial functional magnetic resonance imaging (MRI) can provide directional information on this disease. Muscle biopsy has meaningful value in diagnosing MELAS, which shows the presence of ragged red fibers and mosaic appearance of cytochrome oxidase negative fibers. Genetic studies have reported that approximately 80% of MELAS cases are caused by the mutation m.3243A>G of the mitochondrial transfer RNA (Leu (UUR)) gene (MT-TL1).

CONCLUSIONSMELAS involves multiple systems with variable clinical symptoms and recurrent episodes. The prognosis of MELAS patients depends on timely diagnosis. Therefore, overall diagnosis of MELAS should be based on the maternal inheritance family history, clinical manifestation, and findings from serial MRI, muscle biopsy, and genetics.

Humans ; MELAS Syndrome ; diagnosis ; genetics ; Magnetic Resonance Imaging

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

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

Mitochondrial diseases are clinically and genetically heterogeneous disorders, which make the exact diagnosis and classification difficult. The purpose of this study was to identify pathogenic mtDNA mutations in 61 Korean unrelated families (or isolated patients) with MELAS or MERRF. In particular, the mtDNA sequences were completely determined for 49 patients. From the mutational analysis of mtDNA obtained from blood, 5 confirmed pathogenic mutations were identified in 17 families, and 4 unreported pathogenically suspected mutations were identified in 4 families. The m.3243A>G in the tRNA(Leu(UUR)) was predominantly observed in 10 MELAS families, and followed by m.8344A>G in the tRNA(Lys) of 4 MERRF families. Most pathogenic mutations showed heteroplasmy, and the rates were considerably different within the familial members. Patients with a higher rate of mutations showed a tendency of having more severe clinical phenotypes, but not in all cases. This study will be helpful for the molecular diagnosis of mitochondrial diseases, as well as establishment of mtDNA database in Koreans.
Adolescent ; Adult ; Amino Acid Sequence ; Asian Continental Ancestry Group/genetics ; Base Sequence ; DNA Mutational Analysis ; DNA, Mitochondrial/analysis/*genetics ; Female ; Humans ; MELAS Syndrome/diagnosis/*genetics ; MERRF Syndrome/diagnosis/*genetics ; Male ; Middle Aged ; Molecular Diagnostic Techniques ; Pedigree ; Polymorphism, Single Nucleotide ; Sequence Homology ; Young Adult

PURPOSE: The purpose of this case report is to describe accompanying ocular findings, especially optic neuropathy, in a patient with MELAS syndrome. METHODS: A 10-year-old male patient who had lactic acidosis and neurological symptoms (loss of consciousness, vomiting, epilepsy, decreased vision, and constricted visual field), underwent a brain magnetic resonance imaging (MRI) scan and a molecular genetic analysis. RESULTS: A diagnosis of cerebral infarction due to occlusion in the right posterior cerebral artery was made and confirmed by MRI scan. The diagnosis of MELAS syndrome was confirmed by performing molecular genetic analysis demonstrating the transformation of the mitochondrial tRNAleu(UUR) gene (MTTL1) A to G(3243). According to the ocular examinations, the patient's left eye showed decreased vision, hemianopsia, relative afferent pupillary defects, mild swelling of optic nerve, and decreased amplitude on visual evoked potential exam. CONCLUSIONS: We encountered a case of MELAS syndrome involving optic neuropathy, which can (although rarely) occur with this syndrome. Therefore, in patients with an optic neuropathy of uncertain etiology, clinicians should consider performing comprehensive ocular exams and molecular genetic exams to rule out the possibility of genetic diseases.
Acidosis, Lactic ; Brain ; Cerebral Infarction ; Child ; Consciousness ; Diagnosis ; Epilepsy ; Evoked Potentials, Visual ; Hemianopsia ; Humans ; Magnetic Resonance Imaging ; Male ; MELAS Syndrome* ; Molecular Biology ; Optic Nerve ; Optic Nerve Diseases* ; Posterior Cerebral Artery ; Pupil Disorders ; Vomiting