Taurine ameliorates impaired the mitochondrial function and prevents stroke-like episodes in patients with MELAS.

OBJECTIVE: Post-transcriptional taurine modification at the first anticodon ("wobble") nucleotide is deficient in A3243G-mutant mitochondrial (mt) tRNA(Leu(UUR)) of patients with myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Wobble nucleotide modifications in tRNAs have recently been identified to be important in the accurate and efficient deciphering of codons. We herein examined whether taurine can alleviate mitochondrial dysfunction in patient-derived pathogenic cells and prevent clinical symptoms in MELAS patients. METHODS AND RESULTS: The addition of taurine to the culture media ameliorated the reduced oxygen consumption, decreased the mitochondrial membrane potential, and increased the oxidative stress in MELAS patient-derived cells. Moreover, high dose oral administration of taurine (0.25 g/kg/day) completely prevented stroke-like episodes in two MELAS patients for more than nine years. CONCLUSION: Taurine supplementation may be a novel potential treatment option for preventing the stroke-like episodes associated with MELAS.

Rapid screening for Japanese dysferlinopathy by fluorescent primer extension.

OBJECTIVE: Mutations in the dysferlin gene cause limb-girdle muscular dystrophy (LGMD) 2B and Miyoshi myopathy (MM), which are collectively named dysferlinopathy. Dysferlinopathy is the most frequent type of LGMD in the Japanese population. Molecular genetic analysis is essential for the diagnosis of dysferlinopathy because of its variable immunohistochemical patterns of biopsied muscles, including patterns similar to normal controls. The analysis of the entire dysferlin gene however, is time-consuming and laborious; therefore a simple and rapid screening method to detect hot spot mutations in the dysferlin gene is essential for the diagnosis of dysferlinopathy. METHODS: We previously showed that 4 mutations, c.937+1G>A, c.1566C>G, c.2997G>T and c.3373delG account for 50% of all the mutations identified in Japanese dysferlinopathy patients. We performed a one-tube multiplex PCR, followed by extension of primers for each mutation with a fluorescence-labeled dideoxynucleotide to screen the 4 hot spot mutations. RESULTS: The multiplex primer-extension reaction was developed on samples of known mutations. The extension products were represented as 4 different peaks that corresponded to a mutated nucleotide on electropherogram. Using the developed screening method, we were able to detect mutations in these hot spots in 3 samples out of 8 clinically suspected LGMD2B/MM patients in only approximately 8 hours. These 3 cases were definitely diagnosed as LGMD2B/MM by exonic sequencing. CONCLUSION: We have developed a simple and rapid screening method which could facilitate the definitive diagnosis of dysferlinopathy, contributing to an understanding of the genotype-phenotype correlations for dysferlinopathy.

Hereditary sensory ataxic neuropathy associated with proximal muscle weakness in the lower extremities.

We describe three patients from the same family with hereditary sensory ataxic neuropathy followed by proximal muscle weakness in the lower extremities. Sensory ataxic gait began as an initial symptom when patients were in their 50s. Mild proximal weakness in the lower extremities appeared several years later. Serum creatine kinase was mildly elevated. Nerve conduction studies revealed sensory dominant axonal neuropathy, and short sensory evoked potentials showed involvement of the sensory nerve axon, dorsal root ganglia and posterior funiculus of the spinal cord. Needle electromyography showed fibrillation, positive sharp waves, and multiple giant motor unit potentials, suggesting the involvement of anterior horn motor neurons or the anterior root. Autosomal recessive inheritance was considered, because of consanguinity. The disorder described here may be a new clinical entity with unique clinical manifestations.

[Two brothers with very late onset of muscle weakness in X-linked recessive spinal and bulbar muscular atrophy].

Spinal and bulbar muscular atrophy (SBMA) is a motor neuron disease characterized by slowly progressive spinal and bulbar muscular atrophy associated with signs of androgen insensitivity including gynecomastia. This disease becomes prominent clinically in the fourth and fifth decades of life. Mutations of the androgen receptor (AR) gene associated with an expansion of CAG repeats is the cause of this disease. Here we report a unique family case in two brothers with SBMA with very late onset of muscular weakness. Motor functional symptoms in the two brothers developed at the ages of 66 and 78 years. The number of CAG repeats in the AR gene in both patients was 42. According to previous reports, the number of CAG repeats is related to the age at onset of muscular weakness. Our patient's conditions were consistent with this concept as there was a short expansion of 42 CAG repeats linked to the clinical phenotype of very late onset of muscular weakness. However, the issue of whether the number of CAG repeats is related to the age at onset of androgen insensitivity is still controversial. In the younger brother, gynecomastia appeared in his 20's and preceded the development of muscular weakness by about 40 years, whereas the gynecomastia in the older brother was unremarkable throughout his life. Our brother cases, which had the same number of CAG repeats and should share many common genetic factors, exhibited the androgen insensitivity differed. We therefore consider that an expansion of CAG repeats in the AR gene is not necessarily related to the age at onset of androgen insensitivity. In conclusion, the etiologies of muscular weakness and androgen insensitivity in SBMA could be different.

[A case of isolated CNS sarcoidosis with diffuse confluent high intensity lesions at bilateral deep white matter].

We reported a 60-year-old woman who suffered from isolated neurosarcodosis. She was presenting comprehensive dysfunction and intermittent high fever. In several months she gradually developed dysorientation, amnesia, dementia. However, no focal sign such as paralysis or sensory disturbance was demonstrated. Her blood chemistry showed normal including ACE (angiotensin converting enzyme) and lysozyme. Cerebrospinal fluid revealed elevated mononuclear cells, protein, and decreased glucose level. At first we treated with antibiotics including antiviral drugs in suspect of the infectious encephalomeningitis. But no improvement was observed. The elevation of ACE in spinal fluid made us suspect of neurosarcoidosis. So intravenous predonizoron (1,000 mg) was given, improving. Her high fever and mental disturbance improved. Second spinal fluid showed improvement. During the course her brain MRI revealed new bilateral diffuse confluent high intensity lesions at the deep white matters. Brain biopsy of deep matter at the right anterior lobe showed noncaseating granuloma. Since systemic work-up to detect sarcoidosis did not reveal lesions other than CNS, we considered this patient as having isolated CNS sarcoidosis.