A congenital muscular dystrophy with mitochondrial structural abnormalities caused by defective de novo phosphatidylcholine biosynthesis.

Congenital muscular dystrophy is a heterogeneous group of inherited muscle diseases characterized clinically by muscle weakness and hypotonia in early infancy. A number of genes harboring causative mutations have been identified, but several cases of congenital muscular dystrophy remain molecularly unresolved. We examined 15 individuals with a congenital muscular dystrophy characterized by early-onset muscle wasting, mental retardation, and peculiar enlarged mitochondria that are prevalent toward the periphery of the fibers but are sparse in the center on muscle biopsy, and we have identified homozygous or compound heterozygous mutations in the gene encoding choline kinase beta (CHKB). This is the first enzymatic step in a biosynthetic pathway for phosphatidylcholine, the most abundant phospholipid in eukaryotes. In muscle of three affected individuals with nonsense mutations, choline kinase activities were undetectable, and phosphatidylcholine levels were decreased. We identified the human disease caused by disruption of a phospholipid de novo biosynthetic pathway, demonstrating the pivotal role of phosphatidylcholine in muscle and brain.

[A case of occipital epilepsy with anti-GluRepsilon2 antibody in cerebrospinal fluid, presenting as repeated visual disturbance and headache].

A 78-year-old man was admitted to our hospital with repeated attacks of headache and visual hallucinations, which had begun 10 days before. He also displayed left hemispatial neglect and left homonymous hemianopsia during attacks. Brain magnetic resonance imaging (MRI) showed an abnormal high-intense area in the right occipital lobe on diffusion weighted imaging (DWI) and fluid attenuated inversion recovery (FLAIR) weighted imaging; this lesion was demonstrated as an area of hyperperfusion on ECD-single photon emission computed tomography (SPECT) and hypoperfusion on 123I-BZ-SPECT. Electroencephalography during an attack demonstrated epileptogenic discharges in the right occipital region. Acute urinary retention due to meningoencephalitis appeared 2 weeks after onset of the first attack. Autoantibodies against glutamate receptor epsilon2 were detected in cerebrospinal fluid. We diagnosed the patient with occipital epilepsy due to anti-NMDA receptor antibody encephalitis. Epileptic attacks diminished and MRI and SPECT findings improved following two administrations of intravenous bolus steroid therapy.

[A case of elderly-onset sarcoid myopathy with features resembling polymyositis].

A 75-year-old woman was admitted with a history of acute muscle weakness of her legs for two weeks. Physical examination showed no abnormal findings. Neurological examination revealed symmetrical proximal muscle weakness of legs with muscle pain on grasping. Laboratory data showed normal serum creatine kinase level and marked increases in the levels of serum ACE and soluble interleukin 2. Electromyography showed no myopathic changes. MRI T2 weighted imaging (T2WI) imaging for femoral skeletal muscle demonstrated scattered high and low intensity signals. Muscle biopsy from the right rectus femoris muscle showed granuloma with giant cells of Langhans. She was given a diagnosis of sarcoid myopathy, and motor weakness and abnormal intensity signals on T2WI in this patient were dramatically improved with oral administration of prednisolone (40 mg/day).

Distal lipid storage myopathy due to PNPLA2 mutation.

Distal myopathy is a group of heterogeneous disorders affecting predominantly distal muscles usually appearing from young to late adulthood with very rare cardiac complications. We report a 27-year-old man characterized clinically by distal myopathy and dilated cardiomyopathy, pathologically by lipid storage, and genetically by a PNPLA2 mutation. The patient developed weakness in his lower legs and fingers at age 20 years. Physical examination at age 27 years revealed muscle weakness and atrophy predominantly in lower legs and hands, and severe dilated cardiomyopathy. The patient had a homozygous four-base duplication (c.475_478dupCTCC) in exon 4 of PNPLA2.

[Late-onset leukoencephalopathy without hypertension in a case of young-adult-onset alopecia and spondylosis: a variant of CARASIL?].

We report herein a 61-year-old man with diffuse leukoencephalopathy, subcortical infarcts and cervical and lumbar spondylosis. Medical history included baldness and lumbar spondylosis at young-adult onset. His parents were consanguineous (cousin). He had been experiencing severe lumbago since 20-years-old, with hair loss starting around the same time. He noticed dysarthria and gait disturbance at 59-years-old. He was admitted to our hospital at 61-years-old with aggravation of gait disturbance. On admission, no abnormalities were evident on physical examination except for diffuse baldness. Neurological findings included mild dementia, bilateral hyperreflexia, paraparesis, right Babinski's sign, and pseudobulbar palsy. Blood pressure was normal. T2-weighted imaging of the brain revealed diffuse high-intensity in the periventricular white matter and subcortical infarcts in the brainstem and bilateral basal ganglia. Marked lumbar deformations were observed on spinal MRI. Clinical features in this case met the criteria for cerebral autosomal recessive arteriopathy with subcortical infarctions and leukoencephalopathy (CARASIL), apart from late onset of cerebral infarction.

Effect of L-DOPA on nitric oxide production in striatum of freely mobile mice.

In Parkinson's disease, nitric oxide (NO) and other free radicals are thought to be involved in neuronal degeneration. Furthermore, L-DOPA is suggested to have a cytotoxic action on dopaminergic neurons. We studied 24-h NO production and the effect of L-DOPA on this in freely mobile mice using in vivo microdialysis. A microdialysis probe was implanted into the right striatum 12 h before the experiment. This dialysis probe was perfused with Ringer solution for 100 min, then with 20, 50, or 100 nM L-DOPA for 20 min, and finally with Ringer solution. Dialysate fractions were collected every 20 min for 4 h. Production of nitrite and total NO were significantly higher during daytime than during nighttime. Nitrate production was increased significantly by L-DOPA. NO production in the striatum appears to exhibit a diurnal rhythm and to increase with exposure to L-DOPA.

[Molecular pathomechanism of distal myopathy with rimmed vacuoles].

Distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (HIBM) are genetically identical autosomal recessive muscle disorders caused by mutations in the GNE gene. This gene encodes a bifunctional protein with UDP-GlcNAc 2-epimerase and ManNAc kinase activities that catalyze the rate limiting step and the succeeding step, respectively, in the sialic acid biosynthetic pathway. V572L mutation is the most prevalent among Japanese DMRV patients and accounts for about 60% of mutant alleles. Clinical spectrum of DMRV/HIBM seems to be wider than previously thought in terms of both the severity of the disease and the range of affected organs. There are rare asymptomatic homozygotes with missense GNE mutations, indicating the presence of mitigating factors. Surprisingly, more than 10% of the patients had a variety of cardiac abnormalities, suggesting that skeletal muscle may not be the only organ involved. Studies on recombinant GNE demonstrate a loss-of-function nature of the missense mutations identified. Patients' cells show decreased sialylation status which can be recovered by adding GNE metabolites, such as ManNAc and NeuAc. This indicates the possibility of developing a therapy for DMRV/HIBM by giving these metabolites to patients although we have to await the model mice that are currently being produced at several laboratories.

[Central post-stroke pain in Wallenberg syndrome].

We analyzed clinical characteristics of central post-stroke pain (CPSP), constant and burning pain, in 32 patients with Wallenberg syndrome due to infarction. CPSP developed in 44% (14/32) of the patients; 8 in acute stage (within 4 days after the stroke) and 8 in chronic stage(10-120 days after the stroke). Apart from one exceptional case, CPSP was present in the hypalgesic side of face and extremities. In 9 cases of typical type (Currier's distribution of sensory disturbance), CPSP occurred in the ipsilateral face to the lesion during acute stage. Among them, 2 cases developed severe lancinating pain in chronic stage. In 5 cases of ventral type, it occurred in the contralateral extremities during chronic stage. Spino- and trigemino-thalamic tract are injured but medullary reticular formation is intact in Wallenberg syndrome. It is, therefore, considered that CPSP in Wallenberg syndrome is caused by denervation sensitivity of "paleo-reticulothalamic" tract within the reticular formation.

Oculopharyngeal muscular dystrophy associated with dementia.

We report genetically confirmed heterozygote oculopharyngeal muscular dystrophy (OPMD) accompanied by dementia, suggesting a possible causal association between OPMD and dementia. The proband first noticed bilateral ptosis, dysphagia, and proximal dominant muscle weakness in the lower extremities at age 53. Ten years later, she was found to have dementia with a score of 10/30 on the mini-mental state examination (MMSE). On PABPN1 gene analysis, the GCN repeat was expanded 17 times in one allele. In addition, the proband's younger brother exhibited myopathy and dementia. To our knowledge, this is the first report of genetically confirmed heterozygote OPMD associated with dementia.

Central nervous system and muscle involvement in an adolescent patient with riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency.

We report an adolescent case of late-onset riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency (MADD) characterized by intermittent nausea and depressive state as early symptoms. At the age of 12 years and 11 months, the patient experienced intermittent nausea and vomiting, and depressive state. She was on medication for depression for 5 months but it was ineffective. Brain magnetic resonance imaging showed disseminated high-intensity areas in the periventricular white matter and in the splenium of the corpus callosum on T2-weighted images and fluid-attenuated inversion-recovery images. Progressive muscle weakness occurred and blood creatine kinase level was found to be elevated. The muscle biopsy revealed lipid storage myopathy. Urine organic acid analysis and mutation analysis of the ETFDH gene confirmed the diagnosis of MADD. With oral supplements of riboflavin and l-carnitine, in addition to a high-calorie and reduced-fat diet, her clinical symptoms improved dramatically. Early diagnosis is important because riboflavin treatment has been effective in a significant number of patients with MADD.

ETFDH mutations, CoQ10 levels, and respiratory chain activities in patients with riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency.

Multiple acyl-CoA dehydrogenase deficiency (MADD) is a metabolic disorder due to dysfunction of electron transfer flavoprotein (ETF) or ETF-ubiquinone oxidoreductase (ETF-QO). Mutations in ETFDH, encoding ETF-QO have been associated with both riboflavin-responsive and non-responsive MADD as well as a myopathic form of CoQ(10) deficiency, although pathomechanisms responsible for these different phenotypes are not well-defined. We performed mutation analysis in four Taiwanese MADD patients. Three novel ETFDH mutations were identified in four patients and all harbored the p.A84T mutation. Muscle CoQ(10) levels and respiratory chain activities measured in two patients were normal. Three patients improved on riboflavin together with carnitine. Our results show that not all MADD patients have CoQ(10) deficiency. Based upon our data, riboflavin and carnitine may be the first-line treatment for MADD.

Clinical and genetic analysis of lipid storage myopathies.

Causative genes have been identified only in four types of lipid storage myopathies (LSMs): SLC22A5 for primary carnitine deficiency (PCD); ETFA, ETFB, and ETFDH for multiple acyl-coenzyme A dehydrogenation deficiency (MADD); PNPLA2 for neutral lipid storage disease with myopathy (NLSDM); and ABHD5 for neutral lipid storage disease with ichthyosis. However, the frequency of these LSMs has not been determined. We found mutations in only 9 of 37 LSM patients (24%): 3 in SLC22A5; 4 in MADD-associated genes; and 2 in PNPLA2. This low frequency suggests the existence of other causative genes. Muscle coenzyme Q(10) levels were normal or only mildly reduced in two MADD patients, indicating that ETFDH mutations may not always be associated with CoQ(10) deficiency. The 2 patients with PNPLA2 mutations had progressive, non-episodic muscle disease with rimmed vacuoles. This suggests there is a different pathomechanism from other LSMs.

QSART in idiopathic pure sudomotor failure.

QSART (quantitative sudomotor axon reflex testing) was performed in a patient with idiopathic pure sudomotor failure. Generalized reduction in thermoregulatory sweating and complete absence of axon reflex sweating were observed, suggesting a deficit of sweat gland cholinergic synaptic transmission or receptors. QSART responded promptly to treatment. Putative pathophysiological mechanisms are discussed.