Functionally impaired variants of COQ2 were associated with an increased risk of multiple-system atrophy in multiplex families and patients with sporadic disease, providing evidence of a role of impaired COQ2 activities in the pathogenesis of this disease. (Funded by the Japan Society for the Promotion of Science and others.).

Increased homocysteine levels are associated with various pathological conditions in humans, including stroke and cardiovascular disorders. Homocysteine acts as an excitatory amino acid in vivo and may influence the threshold of migraine headache. Frosst et al. [1995] reported an association between the homozygous C677T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and serum homocysteine levels. This study was designed to determine the prevalence of the MTHFR mutation in Japanese patients with migraine and tension-type headache (TH). Seventy-four patients with migraine headaches (22 with aura and 52 without aura), 47 with THs, and 261 normal controls were recruited. Genotyping of MTHFR C677T polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism. We detected that the incidence of the homozygous transition (T/T) in migraine sufferers (20.3%) was significantly higher than that in controls (9.6%). Moreover, the frequency of the T/T genotype in individuals with migraine headaches with aura was remarkably high (40.9%). The MTHFR T allele was more frequent in the migraine group than in the control group. Our results support the conclusion that the MTHFR gene, causing mild hyperhomocysteinemia may be a genetic risk factor for migraine. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:762-764, 2000.

Acute autonomic and sensory neuropathy is a rare disorder that has been only anecdotally reported. We characterized the clinical, electrophysiological, pathological and prognostic features of 21 patients with acute autonomic and sensory neuropathy. An antecedent event, mostly an upper respiratory tract or gastrointestinal tract infection, was reported in two-thirds of patients. Profound autonomic failure with various degrees of sensory impairment characterized the neuropathic features in all patients. The initial symptoms were those related to autonomic disturbance or superficial sensory impairment in all patients, while deep sensory impairment accompanied by sensory ataxia subsequently appeared in 12 patients. The severity of sensory ataxia tended to become worse as the duration from the onset to the peak phase of neuropathy became longer (P<0.001). The distribution of sensory manifestations included the proximal regions of the limbs, face, scalp and trunk in most patients. It tended to be asymmetrical and segmental, rather than presenting as a symmetric polyneuropathy. Pain of the involved region was a common and serious symptom. In addition to autonomic and sensory symptoms, coughing episodes, psychiatric symptoms, sleep apnoea and aspiration, pneumonia made it difficult to manage the clinical condition. Nerve conduction studies revealed the reduction of sensory nerve action potentials in patients with sensory ataxia, while it was relatively preserved in patients without sensory ataxia. Magnetic resonance imaging of the spinal cord revealed a high-intensity area in the posterior column on T(2)*-weighted gradient echo image in patients with sensory ataxia but not in those without it. Sural nerve biopsy revealed small-fibre predominant axonal loss without evidence of nerve regeneration. In an autopsy case with impairment of both superficial and deep sensations, we observed severe neuronal cell loss in the thoracic sympathetic and dorsal root ganglia, and Auerbach's plexus with well preserved anterior hone cells. Myelinated fibres in the anterior spinal root were preserved, while those in the posterior spinal root and the posterior column of the spinal cord were depleted. Although recovery of sensory impairment was poor, autonomic dysfunction was ameliorated to some degree within several months in most patients. In conclusion, an immune-mediated mechanism may be associated with acute autonomic and sensory neuropathy. Small neuronal cells in the autonomic and sensory ganglia may be affected in the initial phase, and subsequently, large neuronal cells in the sensory ganglia are damaged.

Plasma homocysteine and cysteine levels were measured in 90 patients with PD with the MTHFR C677T (T/T) genotype. The authors found that the levels of homocysteine-a possible risk factor for vascular disease-were elevated by 60% in levodopa-treated patients with PD, with the most marked elevation occurring in patients with the T/T genotype. Cysteine levels in subjects with PD did not differ from levels in control subjects. In the T/T genotype patients, homocysteine and folate levels were inversely correlated. Increased homocysteine might be related to levodopa, MTHFR genotype, and folate in PD.

To explore the clinical significance of restless legs syndrome (RLS) in Parkinson's disease (PD) and the causal relationship between these two disorders, we made a comparison of both the prevalence of RLS and the severity of sleep disturbance manifested on the Pittsburg Sleep Quality Index (PSQI) between patients with PD (n=165) and age- and sex-matched control subjects (n=131). The prevalence of RLS diagnosed by clinical interview was significantly higher in PD patients than in control subjects (12% vs. 2.3%). PSQI score was significantly higher in PD patients with RLS than in both patients without RLS and controls. However, PSQI score was not statistically different between the latter two groups. Among the PD patients with RLS, only 2 had a positive family history of RLS. Only 3 PD patients had requested treatment for the disorder. Our results emphasize the etiological link between RLS and PD in a Japanese cohort, and the existence of RLS is thought to be one of the most important factors aggravating sleep disturbance in PD, despite the low RLS severity.