Learn More
The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related(More)
Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder characterized by the dysfunction of dopaminergic dependent cortico-basal ganglia loops and diagnosed on the basis of motor symptoms (tremors and/or rigidity and bradykinesia). Post-mortem studies tend to show that the destruction of dopaminergic neurons in the substantia nigra constitutes(More)
Motor complications in Parkinson's disease (PD) are associated with long-term oral levodopa treatment and linked to pulsatile dopaminergic stimulation. L-dopa-carbidopa intestinal gel (LCIG) is delivered continuously by percutaneous endoscopic gastrojejunostomy tube (PEG-J), which reduces L-dopa-plasma-level fluctuations and can translate to reduced motor(More)
Previous studies have shown greater atrophy in grey and white matter of various brain regions in patients with Parkinson's disease with mild cognitive impairment than in those without. These anatomical differences likely account for the distinct clinical profiles observed between those groups, but do not account for the evolution of regional brain(More)
Chorea-acanthocytosis (ChAc) is an autosomal recessive neurological disorder whose characteristic features include hyperkinetic movements and abnormal red blood cell morphology. Mutations in the CHAC gene on 9q21 were recently found to cause chorea-acanthocytosis. CHAC encodes a large, novel protein with a yeast homologue implicated in protein sorting. In(More)
Mirror movements are involuntary contralateral movements that mirror voluntary ones and are often associated with defects in midline crossing of the developing central nervous system. We studied two large families, one French Canadian and one Iranian, in which isolated congenital mirror movements were inherited as an autosomal dominant trait. We found that(More)
Tourette syndrome (TS) is a genetically complex disorder for which no causative genes have been unequivocally identified. Nevertheless, a number of molecular genetic studies have investigated several candidate genes, particularly those implicated in dopamine modulation. The results of these studies were inconclusive, which may be due, at least in part, to(More)
Numerous studies have explored the potential relationship between rapid eye movement sleep behavior disorder (RBD) and manifestations of PD. Our aim was to perform an expanded extensive assessment of motor and nonmotor manifestations in PD to identify whether RBD was associated with differences in the nature and severity of these manifestations. PD patients(More)
UNLABELLED Studies assessing the efficacy of nicotine in Parkinson's disease (PD) have generated contradictory results. The controversy seems to stem from uncontrolled factors including the lack of objective measures, the practice effect in a test-retest design, and the absence of plasmatic dosage. This study aimed at further controlling these factors using(More)
BACKGROUND Dystonia must be accurately diagnosed so that treatment can be administered promptly. However, dystonia is a complex disorder, with variable presentation, which can delay diagnosis. METHODS Data were gathered by questionnaire from 866 patients with dystonia or hemifacial spasm (HFS) treated in 14 movement disorders centres in Canada injecting(More)