VPS35 mutation in Japanese patients with typical Parkinson's disease.

Vacuolar protein sorting 35 (VPS35) was recently reported to be a pathogenic gene for late-onset autosomal dominant Parkinson's disease (PD), using exome sequencing. To date, VPS35 mutations have been detected only in whites with PD. The aim of the present study was to determine the incidence and clinical features of Asian PD patients with VPS35 mutations. We screened 7 reported nonsynonymous missense variants of VPS35, including p.D620N, known as potentially disease-associated variants of PD, in 300 Japanese index patients with autosomal dominant PD and 433 patients with sporadic PD (SPD) by direct sequencing or high-resolution melting (HRM) analysis. In addition, we screened 579 controls for the p.D620N mutation by HRM analysis. The p.D620N mutation was detected in 3 patients with autosomal dominant PD (1.0%), in 1 patient with SPD (0.23%), and in no controls. None of the other reported variants of VPS35 were detected. Haplotype analysis suggested at least 3 independent founders for Japanese patients with p.D620N mutation. Patients with the VPS35 mutation showed typical tremor-predominant PD. We report Asian PD patients with the VPS35 mutation. Although VPS35 mutations are uncommon in PD, the frequency of such mutation is relatively higher in Japanese than reported in other populations. In VPS35, p.D620N substitution may be a mutational hot spot across different ethnic populations. Based on the clinical features, VPS35 should be analyzed in patients with PD, especially autosomal dominant PD or tremor-predominant PD.

[Nasal flaring during hypoxemia in myotonic dystrophy and duchenne muscular dystrophy].

We investigated the relationship between nasal flaring and SpO2 in 19 patients with Duchenne muscular dystrophy (DMD) and 26 patients with myotonic dystrophy (DM1). In DMD patients, nasal flaring was observed when SpO2 was lower than 96%, while it was not seen even at 82% of SpO2 in DM1. None of the DM1 patients could perform voluntary nasal flaring. Nasal flaring is a useful indicator of hypoxemia in DMD but not in DM1. It remains to be elucidated whether the lack of nasal flaring in DM1 patients is due to abnormal respiratory central mechanism or nasal muscle weakness.

¹¹C-PiB PET imaging of encephalopathy associated with cerebral amyloid angiopathy.

We herein report that the clinical, laboratory, and radiographic features and positron emission tomography (PET) imaging may provide valuable clues to the pathogenesis of cerebral amyloid angiopathy (CAA)-associated encephalopathy, which currently remains unclear. We herein describe two cases of encephalopathy with CAA, with an emphasis on PET imaging with (11)C-Pittsburgh compound B ((11)C-PiB) and (18)F-fluorodeoxyglucose ((18)F-FDG). One case of Alzheimer's disease for which a brain biopsy was performed showed CAA-related inflammation. Another case that had developed sudden sensory aphasia presented with posterior reversible encephalopathy syndrome-like vasogenic edema in the left temporal region with (11)C-PiB uptake and microhemorrhages. (11)C-PiB and (18)F-FDG PET are useful for detecting CAA-associated encephalopathy, including atypical CAA cases.

Identification of the 1,2-propanediol-1-yl radical as an intermediate in adenosylcobalamin-dependent diol dehydratase reaction.

The reaction catalyzed by adenosylcobalamin-dependent diol dehydratase proceeds by a radical mechanism. A radical pair consisting of the Co(II) of cob(II)alamin and an organic radical intermediate formed during catalysis gives EPR spectra. The high-field doublet and the low-field broad signals arise from the weak interaction of an organic radical with the low-spin Co(II) of cob(II)alamin. To characterize the organic radical intermediate in the diol dehydratase reaction, several deuterated and (13)C-labeled 1,2-propanediols were synthesized, and the EPR spectra observed in the catalysis were measured using them as substrate. The EPR spectra with the substrates deuterated on C1 showed significant line width narrowing of the doublet signal. A distinct change in the hyperfine coupling was seen with [1-(13)C]-1,2-propanediol, but not with the [2-(13)C]-counterpart. Thus, the organic radical intermediate observed by EPR spectroscopy was identified as the 1,2-propanediol-1-yl radical, a C1-centered substrate-derived radical.