Beasley, Alexandra I

BackgroundRecently, a novel mutation in exon 24 of DNAJC13 gene (p.Asn855Ser, rs387907571) has been reported to cause autosomal dominant Parkinson's disease (PD) in a multi‐incident Mennonite family.MethodsIn the present study the mutation containing exon of the DNAJC13 gene has been sequenced in a Caucasian series consisting of 1938 patients with clinical PD and 838 with pathologically diagnosed Lewy body disease (LBD).ResultsOur sequence analysis did not identify any coding variants in exon 24 of DNAJC13. Two previously described variants in intron 23 (rs200204728 and rs2369796) were observed.ConclusionOur results indicate that the region surrounding the DNAJC13 p.Asn855Ser substitution is highly conserved and mutations in this exon are not a common cause of PD or LBD among Caucasian populations.

Background and purposeLow density lipoprotein receptor related proteins (LRPs) 1 and 6 have been implicated in cerebral ischaemia. In addition, genetic variation in LRP1 and LRP6 has been linked with various factors that are related to risk of ischaemic stroke. The aim of this study was to examine the association of LRP1 and LRP6 gene variants with risk of ischaemic stroke as part of the Ischemic Stroke Genetics Study (ISGS).MethodsA Caucasian series (434 stroke patients, 319 controls) and an African American series (161 stroke patients, 116 controls) were included. Fourteen LRP6 variants and three LRP1 variants were genotyped and assessed for association with ischaemic stroke.ResultsIn the Caucasian series, significant associations with ischaemic stroke were observed for LRP6 rs2075241 [odds ratio (OR) 0.42, P = 0.023], rs2302685 (OR 0.44, P = 0.049), rs7975614 (OR 0.07, P = 0.017), rs10492120 (OR 0.62, P = 0.036) and rs10743980 (OR 0.66, P = 0.037). Risk of ischaemic stroke was significantly lower for carriers of any of these five protective LRP6 variants (24.0% of subjects) compared to non‐carriers (OR 0.57, P = 0.003). The protective association for LRP6 rs2075241 was observed at a similar magnitude across ischaemic stroke subtypes, whilst the effects of rs23022685, rs10492120 and rs10743980 were most apparent for cardioembolic and large vessel stroke. In the African American series, LRP1 rs11172113 was associated with an increased risk of stroke (OR 1.89, P = 0.006).ConclusionsThe results of our preliminary study provide evidence that LRP6 and LRP1 variants may be associated with risk of ischaemic stroke. Validation in larger studies is warranted.

ABSTRACTBackgroundVariants within the leucine‐rich repeat kinase 2 gene are recognized as the most frequent genetic cause of Parkinson's disease. Leucine‐rich repeat kinase 2 variation related to disease susceptibility displays many features that reflect the nature of complex, late‐onset sporadic disorders like Parkinson's disease.MethodsThe Genetic Epidemiology of Parkinson's Disease Consortium recently performed the largest genetic association study for variants in the leucine‐rich repeat kinase 2 gene across 23 different sites in 15 countries.ResultsHerein, we detail the allele frequencies for the novel risk factors (p.A419V and p.M1646T) and the protective haplotype (p.N551K‐R1398H‐K1423K) nominated in the original publication. Simple population allele frequencies not only can provide insight into the clinical relevance of specific variants but also can help genetically define patient groups.ConclusionsEstablishing individual patient‐based genomic susceptibility profiles that incorporate both risk factors and protective factors will determine future diagnostic and treatment strategies. © 2013 International Parkinson and Movement Disorder Society

BackgroundIschaemic stroke shares common traditional risk factors with coronary artery disease (CAD) and myocardial infarction (MI). This study evaluated whether genetic risk factors for CAD and MI also affect susceptibility to ischaemic stroke in Caucasians and African Americans.MethodsIncluded in the study were a Caucasian series (713 ischaemic stroke patients, 708 controls) and a small African American series (166 ischaemic stroke patients, 117 controls). Twenty single‐nucleotide polymorphisms (SNPs) previously shown to be associated with CAD or MI were genotyped and assessed for association with ischaemic stroke and ischaemic stroke subtypes using odds ratios (ORs) from multivariable logistic regression models.ResultsIn Caucasians, four SNPs on chromosome 9p21 were significantly associated with risk of cardioembolic stroke, the strongest of which was rs1333040 (OR 1.55, P = 0.0007); similar but weaker trends were observed for small vessel stroke, with no associations observed regarding large vessel stroke. Chromosome 9p21 SNPs were also associated with risk of ischaemic stroke in African Americans (rs1333040, OR 0.65, P = 0.023; rs1333042, OR 0.55, P = 0.070; rs2383207, OR 0.55, P = 0.070). The PSMA6 SNP rs1048990 on chromosome 14q13 was associated with overall ischaemic stroke in both Caucasians (OR 0.80, P = 0.036) and African Americans (OR 0.31, P = 0.020).ConclusionsOur results provide evidence that chromosome 9p21 variants are associated with cardioembolic ischaemic stroke in Caucasians and with overall ischaemic stroke in African Americans. The PSMA6 variant rs1048990 also appears to affect susceptibility to ischaemic stroke in both populations. These findings require validation, particularly the preliminary findings regarding African Americans given the small size of that series.