Genome-wide association study of Parkinson's disease in East Asians.

Genome-wide association studies (GWAS) on Parkinson's disease (PD) have mostly been done in Europeans and Japanese. No study has been done in Han Chinese, which make up nearly a fifth of the world population. We conducted the first Han Chinese GWAS analysing a total of 22,729 subjects (5,125 PD cases and 17,604 controls) from Singapore, Hong Kong, Malaysia, Korea, mainland China and Taiwan. We performed imputation, merging and logistic regression analyses of 2,402,394 SNPs passing quality control filters in 779 PD cases, 13,227 controls, adjusted for the first three principal components. 90 SNPs with association P < 10-4 were validated in 9 additional sample collections and the results were combined using fixed-effects inverse-variance meta-analysis. We observed strong associations reaching genome-wide significance at SNCA, LRRK2 and MCCC1, confirming their important roles in both European and Asian PD. We also identified significant (P < 0.05) associations at 5 loci (DLG2, SIPA1L2, STK39, VPS13C and RIT2), and observed the same direction of associations at 9 other loci including BST1 and PARK16. Allelic heterogeneity was observed at LRRK2 while European risk SNPs at 6 other loci including MAPT and GBA-SYT11 were non-polymorphic or very rare in our cohort. Overall, we replicate associations at SNCA, LRRK2, MCCC1 and 14 other European PD loci but did not identify Asian-specific loci with large effects (OR > 1.45) on PD risk. Our results also demonstrate some differences in the genetic contribution to PD between Europeans and Asians. Further pan-ethnic meta-analysis with European GWAS cohorts may unravel new PD loci.

A cross-sectional study of COVID-19 vaccination patterns among patients with epilepsy in Hong Kong.

OBJECTIVE: As Hong Kong faced the 5th wave of the COVID-19 pandemic, the facilitators and hurdles toward effective vaccination is important for healthcare professionals to understand the vaccination gap among patients with epilepsy. METHODS: A cross-sectional, pragmatic study of COVID-19 vaccination was performed at a tertiary epilepsy center with regards to patterns of vaccination and any unusually high rate of adverse events. Patients having recent visits at the epilepsy center (4 months) had their anonymized electronic linkage records examined 12 months after the inception of vaccination program for types of vaccines, seizure demographics, and adverse events following immunization (AEFI). RESULTS: A total of 200 patients with epilepsy and their anonymized data were analyzed. The vaccine uptake was approximately 60% of that of the general population. Twice as many patients with epilepsy chose to receive mRNA vaccine as compared with inactivated vaccine. The proportion of patients who kept up-to-date with all available dosing was 7%. Patients with epilepsy with genetic etiology were least likely to receive vaccination (13/38, 34%, P = .02). There was no unreasonably high rate of unacceptable side effects after vaccination among patients with epilepsy. Only 3 patients reported worsening of seizures without meeting the criteria for AEFI. Refractory epilepsy, allergy to antiseizure medications and elder age (≥65) did not confer any significant difference in vaccination patterns or adverse effects. SIGNIFICANCE: A vaccination gap exists among epilepsy patients which calls for actionable strategies for improving vaccine uptake, including education and outreach programs.

Risk factors for delayed-onset dementia after stroke or transient ischemic attack-A five-year longitudinal cohort study.

BACKGROUND: Stroke not only substantially increases the risk of incident dementia early after stroke but also the risk remains elevated years after. AIM: We aimed to determine the risk factors of dementia onset more than three to six months after stroke or transient ischemic attack. METHODS: This is a single-center prospective cohort study. We recruited consecutive subjects with stroke/transient ischemic attack without early-onset dementia. We conducted an annual neuropsychological assessment for five years. We investigated the association between baseline demographic, clinical, genetic (APOEɛ4 allele), and radiological factors as well as incident recurrent stroke with delayed-onset dementia using Cox proportional hazards models. RESULTS: In total, 1007 patients were recruited, of which 88 with early-onset dementia and 162 who lost to follow-ups were excluded. Forty-nine (6.5%) out of 757 patients have incident delayed-onset dementia. The presence of ≥3 lacunes, history of ischemic heart disease, history of ischemic stroke, and a lower baseline Hong Kong version of the Montreal Cognitive Assessment (MoCA) score were significantly associated with delayed-onset dementia. APOEɛ4 allele, medial temporal lobe atrophy, and recurrent stroke were not predictive. CONCLUSION: The presence of ≥3 lacunes, history of ischemic heart disease, history of ischemic stroke, and a lower baseline MoCA score are associated with delayed-onset dementia after stroke/transient ischemic attack.

Eye movement parameters and cognitive functions in Parkinson's disease patients without dementia.

BACKGROUND: Cognitive deficits and eye movement abnormalities have been demonstrated to be detectable early clinical manifestations of Parkinson's disease. Understanding the relationship between these phenotypes may yield insight into the underlying anatomical pathways, assisting in the search for simple non-invasive markers of early neurodegeneration. OBJECTIVE: To explore the correlations between eye movement parameters with multi-domain cognitive functions in patients suffering from Parkinson's disease without dementia. METHOD: This is a cross-sectional case-control study of Parkinson's disease patients without dementia. Participants underwent global and domain-specific cognitive tests and an eye-tracking visual search task to characterize eye movement parameters. RESULTS: 62 Chinese Parkinson's disease patients without dementia and 62 sex-, age- and education-matched controls were recruited. The disease group performed worse in multiple cognitive tasks and exhibited a smaller saccadic amplitude. Negative correlations between the eye fixation duration and performance in semantic verbal fluency, verbal and visual recognition memory tasks were observed, though there was no moderation effect on the correlations due to the presence of Parkinson's disease. A common cholinergic deficit in the temporal and parietal regions may account for the observed correlations. The lack of association with predominantly frontal-executive tasks may suggest specificity of these correlations. CONCLUSION: Prolonged visual fixation duration is correlated with poorer performance in semantic verbal fluency, verbal and visual recognition memory tasks in Parkinson's disease patients without dementia, although these correlations are not specific. The clinical utility of eye movement parameters as an early marker for cognitive decline in Parkinson's disease warrants further exploration in longitudinal studies.