Background: The overlap in the clinical and pathological features of tauopathies and synucleinopathies raises the possibility that the tau protein may be important in Parkinson’s disease (PD) pathogenesis. Several MAPT polymorphisms that define the tau H1 haplotype have been investigated for an association with PD with conflicting results; however, two meta-analyses support an association between haplotype H1 and PD. Methods: In this study, we recruited 508 patients and 611 healthy controls from Greek, Finnish and Taiwanese populations. We examined the possible genetic role of variation within MAPT in PD using haplotype-tagging single polymorphisms (SNPs) in these ethnically different PD populations. Results: We identified a moderate association at SNP rs3785883 in the Greek cohort for both allele and genotype frequency (p = 0.01, p = 0.05, respectively) as well as for SNP rs7521 (genotype p = 0.02) and rs242557 (p = 0.01 genotypic, p = 0.04 allelic) in the Finnish population. There were no significant differences in genotype or allele distribution between cases and controls in the Taiwanese cohort. Conclusion: We failed to demonstrate a consistent association between the MAPT H1 haplotype (delineated by intron 9 ins/del) and PD in three ethnically diverse populations. However, the data presented here suggest that subhaplotypes of haplotype H1 may confer susceptibility to PD, and that either allelic heterogeneity or different haplotype composition explain the divergent haplotype results.

Background: We and others recently identified the gene underlying PARK8 linked Parkinson's disease (PD). This gene, LRRK2, contains mutations that cause an autosomal dominant PD, including a mutation, G2019S, which is the most common PD causing mutation identified to date. Common genetic variability in genes that contain PD causing mutations has previously been implicated as a risk factor for typical sporadic disease. Methods: We undertook a case-control association analysis of LRRK2 in two independent European PD cohorts using 31 tagging single nucleotide polymorphisms (tSNPs) and five potentially functional SNPs. To assess the structure of this locus in different populations, we have performed linkage disequilibrium (LD) analysis using these variants in a human diversity panel. Results: We show that common genetic variability in LRRK2 is not associated with risk for PD in the European populations studied here. We also show inter-population variability in the strength of LD across this locus. Conclusions: To our knowledge this is the first comprehensive analysis of common variability within LRRK2 as a risk factor for PD.

The objective of this study was to investigate whether the findings of MR imaging and MR angiography could accurately and early diagnose brain death in comatose patients. Thirty comatose patients were studied with MRI and MR arteriography. In 20 patients (group A) presenting with a Glasgow coma scale (GCS) 3-6, the final clinical diagnosis was brain death. In ten comatose patients with a GCS 4-6 and no clinical signs of brain death (group B), the clinical follow-up did not reveal brain death in a period of 12 months. The MRI examination consisted of turbo fluid-attenuated inversion recovery and T2 turbo spin-echo pulse sequences. The MR arteriography was performed with a 3D inflow pulse sequence. In 12 patients with brain death and 5 patients with no signs of brain death, a 3D phase contrast MR venography was also ap-plied. Magnetic resonance imaging in all patients showed variable edema with swelling of the cerebral gyri, small ventricular system, and basilar subarachnoid spaces. In group A, MRI in addition showed tonsillar herniation. In group A, MR arteriography revealed no arterial flow in the intracranial circulation, whereas MR venography showed in 9 patients no opacification of the sagittal and straight sinuses or visualization of intracranial veins. In contrast, MR angiography showed intact intracranial vessels in patients of group B. In conclusion, MR imaging and MR angiography may be reliable ancillary tests for use in early diagnosis of brain death and further work is required to validate its utility.