Biased wrist and finger coordination in Parkinsonian patients during performance of graphical tasks.

Handwriting impairments in Parkinson's disease (PD) have been associated with micrographia, i.e. diminished letter size.

Submovements during pointing movements in Parkinson's disease.

Velocity irregularities frequently observed during deceleration of arm movements have usually been interpreted as corrective submovements that improve motion accuracy. This hypothesis is re-examined here in application to movements of Parkinson's disease (PD) patients in which submovements are specifically frequent. Pointing movements in patients and age-matched controls to large and small targets in three movement modes were studied.

Genetic association between alpha-synuclein and idiopathic Parkinson's disease.

Point mutations and copy number variations in SNCA, the gene encoding alpha-synuclein, cause familial Parkinson's disease (PD). A dinucleotide polymorphism (REP1) in the SNCA promoter may be a risk factor for common forms of PD. We studied 1,802 PD patients and 2,129 controls from the NeuroGenetics Research Consortium, using uniform, standardized protocols for diagnosis, subject recruitment, data collection, genotyping, and data analysis.

Glucocerebrosidase gene mutations: a risk factor for Lewy body disorders.

Background: Mutations in the glucocerebrosidase (GBA) gene have been reported to modify risk for Parkinson disease (PD) and dementia with Lewy bodies (DLB). However, these findings have not been consistently replicated, and most studies have had substantial methodological shortcomings.

Objective: To better assess the role of GBA variants in altering risk for Lewy body disorders.

Exploring gene-environment interactions in Parkinson's disease.

The objective of this study was to explore combined effects of four candidate susceptibility genes and two exposures on Parkinson's disease (PD) risk; namely, alpha-synuclein (SNCA) promoter polymorphism REP1, microtubule-associated protein tau (MAPT) H1/H2 haplotypes, apolipoprotein E (APOE) epsilon2/epsilon3/epsilon4 polymorphism, ubiquitin carboxy-terminal esterase L1 (UCHL1) S18Y variant, cigarette smoking and caffeinated coffee consumption. 932 PD patients and 664 control subjects from the NeuroGenetics Research Consortium, with complete data on all six factors, were studied. Uniform protocols were used for diagnosis, recruitment, data collection and genotyping.

Lack of evidence for an association between UCHL1 S18Y and Parkinson's disease.

UCHL1 has been proposed as a candidate gene for Parkinson's disease (PD). A meta-analysis of white and Asian subjects reported an inverse association between the non-synonymous UCHL1 S18Y polymorphism and PD risk. However, this finding was not replicated in a large case-control study and updated meta-analysis restricted to white subjects.

Association analysis of MAPT H1 haplotype and subhaplotypes in Parkinson's disease.

Objective: An inversion polymorphism of approximately 900 kb on chromosome 17q21, which includes the microtubule-associated protein tau (MAPT) gene defines two haplotype clades, H1 and H2. Several small case-control studies have observed a marginally significant excess of the H1/H1 diplotype among patients with Parkinson's disease (PD), and one reported refining the association to a region spanning exons 1 to 4 of MAPT. We sought to replicate these findings.

DBH -1021C-->T does not modify risk or age at onset in Parkinson's disease.

DBH is a candidate gene in Parkinson's disease (PD) and contains a putative functional polymorphism (-1021C-->T) that has been reported to modify PD susceptibility. We examined -1021C-->T in a sample of 1,244 PD patients and 1,186 unrelated control subjects. There was no significant difference in allele (p = 0.

Validity and utility of a LRRK2 G2019S mutation test for the diagnosis of Parkinson's disease.

The G2019S mutation in the LRRK2 gene, the most common known cause of Parkinson's disease (PD), will soon be widely available as a molecular clinical test for PD. The objective of this study was to assess performance characteristics of G2019S as a clinical test for PD in the setting of typical movement disorder clinics in the United States. Subjects included 1,518 sequentially recruited PD patients from seven movement disorder clinics in the United States, and 1,733 unaffected subjects.

LRRK2 G2019S in families with Parkinson disease who originated from Europe and the Middle East: evidence of two distinct founding events beginning two millennia ago.

The leucine-rich repeat kinase 2 (LRRK2) G2019S mutation is the most common genetic determinant of Parkinson disease (PD) identified to date. It accounts for 1%-7% of PD in patients of European origin and 20%-40% in Ashkenazi Jews and North African Arabs with PD. Previous studies concluded that patients from these populations all shared a common Middle Eastern founder who lived in the 13th century.

Altered coordination patterns in parkinsonian patients during trunk-assisted prehension.

We examined whether coordination between movement components during trunk-assisted prehension was compromised in PD patients in response to varying constraints (experiment 1: reach speed, object size, movement amplitude; experiment 2: movement sequence). In general, both PD patients and controls responded similarly to the changes in these three variables. PD patients, however, demonstrated less synchronized movements in terms of timing between onsets and offsets of aperture formation, endpoint motion and trunk motion.

Disruptions in joint control during drawing arm movements in Parkinson's disease.

Impairments in control of multi-joint arm movements in Parkinson's Disease (PD) were investigated. The PD patients and age-matched elderly participants performed cyclical arm movements, tracking templates of a large circle and four differentially oriented ovals on a horizontal table. The wrist was immobilized and the movements were performed with shoulder and elbow rotations.