Parkinson Disease: Singleton A

Singleton A, Morris H. · No affiliation provided · Neurology. · Pubmed #18591501 No free full text.

This publication has no abstract.

Singleton A. · No affiliation provided · Neurology. · Pubmed #15505146 No free full text.

This publication has no abstract.

Bras J, Singleton A, Cookson MR, Hardy J. · Molecular Genetics Unit, National Institutes on Aging, Bethesda, MD, USA. · FEBS J. · Pubmed #19021754 No free full text.

Abstract: Heterozygous loss-of-function mutations at the glucosecerebrosidase locus have recently been shown to be a potent risk factor for Lewy body disease. Based on this observation, we have re-evaluated the likelihood that the different PARK loci (defined using clinical criteria for disease) may be misleading attempts to find common pathways to pathogenesis. Rather, we suggest, grouping the different loci which lead to different Lewy body disease may be more revealing. Doing this, we suggest that several of the genes involved in disparate Lewy body diseases impinge on ceramide metabolism and we suggest that this may be a common theme for pathogenesis.

Greggio E, Singleton A. · Cell Biology & Gene Expression Unit, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20982, USA. · Expert Rev Proteomics. · Pubmed #18067416 No free full text.

Abstract: Parkinson's disease (PD) is a severe, progressive, age-associated, neurodegenerative disorder. Current therapies are symptomatic and not effective at halting or significantly slowing the disease progress. The search for etiologic-based therapies has focused largely on genetic findings made in familial forms of this disease. Mutations of five genes have been unequivocally linked to PD; two of these, LRRK2 and PINK1, encode kinases and as such are attractive tools with which to understand the disease process; furthermore, preliminary functional data suggests that these proteins, or the pathways in which they are involved, are viable therapeutic targets. Here we explore the current data and thoughts regarding LRRK2 and PINK1 and discuss further avenues of research to understand the pathologic effects of mutations at these loci and potential points of therapeutic intervention, such as within these kinases or in associated pathways such as Jun N-terminal kinase and Akt pathways.

Hardy J, Cai H, Cookson MR, Gwinn-Hardy K, Singleton A. · Laboratory of Neurogenetics, National Institute on Aging, Porter Neuroscience Building, 35 Convent Drive, Bethesda, MD 20892, USA. · Ann Neurol. · Pubmed #17068789 No free full text.

Abstract: Until 10 years ago, conventional wisdom held that Parkinson's disease was not a genetic disorder. Since that time, there have been a plethora of genetic findings, culminating in the cloning of several genes that derive from the loci given the nomenclature PARK1-PARK12 (OMIM 168600). Recently, these research findings have begun to impact clinical practice, and this impact is likely to increase. The primary purpose of this article is to outline these genetic advances, discuss their importance for current practice in clinical and related settings, and outline briefly how they are influencing research into the causes of and possible future treatments for this prevalent disorder.

Hernandez D, Paisan Ruiz C, Crawley A, Malkani R, Werner J, Gwinn-Hardy K, Dickson D, Wavrant Devrieze F, Hardy J, Singleton A. · Laboratory of Neurogenetics, National Institutes on Aging and of Neurological Diseases and Stroke, Bethesda, MD 20892, USA. · Neurosci Lett. · Pubmed #16102903 No free full text.

Abstract: Mutations in the leucine-rich kinase 2 gene (LRRK 2) encoding dardarin, on chromosome 12, are a common cause of familial and sporadic Parkinson's disease. The most common mutation, a heterozygous 6055 G>A transition (G 2019 S) accounts for approximately 3--10% of familial Parkinson's disease and 1--8% sporadic Parkinson's disease in several European-derived populations. Some families with disease caused by LRRK 2 mutations have been reported to include patients with highly variable clinical and pathological features. We screened for the most common LRRK 2 mutation in a series of patients with Parkinson's Disease, Alzheimer's disease, Progressive Supranuclear Palsy, Multiple System Atrophy and frontotemporal dementia, as well as in neurologically normal controls. The mutation was found only in Parkinson's disease patients or their relatives and not in those with other neurodegenerative disease.

Evidente VG, Esteban RP, Hernandez JL, Natividad FF, Advincula J, Gwinn-Hardy K, Hardy J, Singleton A, Singleton A. · Department of Neurology, Mayo Clinic, 13400 E. Shea Boulevard, Scottsdale, AZ 85259, USA. · Parkinsonism Relat Disord. · Pubmed #15465396 No free full text.

Abstract: We administered a culturally corrected University of Pennsylvania Smell Identification Test (ccUPSIT) consisting of 25 odor items to 20 patients with 'Lubag' or X-linked dystonia-parkinsonism and 20 control subjects matched by sex, age, educational background, smoking history, and geographical origin. The mean ccUPSIT score of Lubag patients (18 +/- 3.19) was statistically lower (P = 0.003) than controls (20.5 +/- 3.02). The smell scores did not correlate with phenotype, severity of dystonia, or duration of disease. Nine of 20 Lubag patients (45%) had ccUPSIT scores below the mean, with the lowest score being 11. This pilot study suggests that olfactory dysfunction may occur in Lubag patients.

Evidente VG, Esteban RP, Hernandez JL, Natividad FF, Advincula J, Gwinn-Hardy K, Hardy J, Singleton A, Singleton A. · Department of Neurology, Mayo Clinic, 13400 E. Shea Boulevard, Scottsdale, AZ 85259, USA. · Parkinsonism Relat Disord. · Pubmed #15465396 No free full text.

Abstract: We administered a culturally corrected University of Pennsylvania Smell Identification Test (ccUPSIT) consisting of 25 odor items to 20 patients with 'Lubag' or X-linked dystonia-parkinsonism and 20 control subjects matched by sex, age, educational background, smoking history, and geographical origin. The mean ccUPSIT score of Lubag patients (18 +/- 3.19) was statistically lower (P = 0.003) than controls (20.5 +/- 3.02). The smell scores did not correlate with phenotype, severity of dystonia, or duration of disease. Nine of 20 Lubag patients (45%) had ccUPSIT scores below the mean, with the lowest score being 11. This pilot study suggests that olfactory dysfunction may occur in Lubag patients.

Okubadejo N, Britton A, Crews C, Akinyemi R, Hardy J, Singleton A, Bras J. · Neurology Unit, Department of Medicine, College of Medicine, University of Lagos, Lagos, Nigeria. · PLoS One. · Pubmed #18927607 links to  free full text

Abstract: Several genetic variations have been associated with Parkinson disease in different populations over the past few years. Although a considerable number of worldwide populations have been screened for these variants, results from Sub-Saharan populations are very scarce in the literature. In the present report we have screened a cohort of Parkinson disease patients (n = 57) and healthy controls (n = 51) from Nigeria for mutations in the genes PRKN, LRRK2 and ATXN3. No pathogenic mutations were found in any of the genes. Hence, common pathogenic mutations in these genes, observed in several different populations, are not a frequent cause of Parkinson disease in Nigeria.

Bras J, Guerreiro R, Ribeiro M, Morgadinho A, Januario C, Dias M, Calado A, Semedo C, Oliveira C, Hardy J, Singleton A. · Center for Neurosciences and Cell Biology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal. · BMC Neurol. · Pubmed #18211709 links to  free full text

Abstract: BACKGROUND: Mutations in the genes PRKN and LRRK2 are the most frequent known genetic lesions among Parkinson's disease patients. We have previously reported that in the Portuguese population the LRRK2 c.6055G > A; p.G2019S mutation has one of the highest frequencies in Europe. METHODS: Here, we follow up on those results, screening not only LRRK2, but also PRKN, SNCA and PINK1 in a cohort of early-onset and late-onset familial Portuguese Parkinson disease patients. This series comprises 66 patients selected from a consecutive series of 132 patients. This selection was made in order to include only early onset patients (age at onset below 50 years) or late-onset patients with a positive family history (at least one affected relative). All genes were sequenced bi-directionally, and, additionally, SNCA, PRKN and PINK1 were subjected to gene dosage analysis. RESULTS: We found mutations both in LRRK2 and PRKN, while the remaining genes yielded no mutations. Seven of the studied patients showed pathogenic mutations, in homozygosity or compound heterozygosity for PRKN, and heterozygosity for LRRK2. CONCLUSION: Mutations are common in Portuguese patients with Parkinson's disease, and these results clearly have implications not only for the genetic diagnosis, but also for the genetic counseling of these patients.

Bras J, Paisan-Ruiz C, Guerreiro R, Ribeiro MH, Morgadinho A, Januario C, Sidransky E, Oliveira C, Singleton A. · Laboratory of Neurogenetics, National Institutes on Aging, National Institutes of Health, Bethesda, MD 20892, USA. · Neurobiol Aging. · Pubmed #18160183 No free full text.

Abstract: Mutations in the gene encoding beta-glucocerebrosidase, a lysosomal degrading enzyme, have recently been associated with the development of Parkinson disease. Here we report the results found in a cohort of Portuguese Parkinson disease patients and healthy age-matched controls for mutations in the aforementioned gene. This screening was accomplished by sequencing the complete open-reading frame, as well as intron/exon boundaries, of the glucocerebrosidase gene, in a total of 230 patients and 430 controls. We have found an increased number of Parkinson disease patients presenting mutations in GBA when compared to controls. These results, together with recent literature, clearly suggest a role of glucocerebrosidase in the development of Parkinson disease.

Simon-Sanchez J, Scholz S, Matarin Mdel M, Fung HC, Hernandez D, Gibbs JR, Britton A, Hardy J, Singleton A. · Molecular Genetics Unit, National Institutes of Health, Bethesda, Maryland 20892, USA. · Hum Mutat. · Pubmed #17994548 No free full text.

Abstract: Technologies that allow genotyping of more than 100,000 polymorphisms in a single assay enable the execution of genomewide SNP (GWSNP) association studies to identify common genetic variants underlying traits. Less appreciated is the ability of GWSNP assays to map and directly identify rare mutations that cause disease. Here we show the use of this approach in identifying rare structural mutations involved in disease using a large cohort of Parkinson disease (PD) patients and neurologically normal controls by examination of genotype data and copy number metrics. This approach revealed a patient with homozygous mutation at the PARK2 locus. In addition, two heterozygous deletion mutations and five heterozygous duplication mutations within PARK2 were identified in PD subjects and controls. All mutations were confirmed by independent gene dosage experiments. These data demonstrate the utility of this approach in the direct detection of mutations that underlie disease.

Goldstein DS, Imrich R, Peckham E, Holmes C, Lopez G, Crews C, Hardy J, Singleton A, Hallett M. · Clinical Neurocardiology Section, National Institutes on Neurological Disorders and Stroke, National Institute on Aging, NIH, Bethesda, MD 20892-1620, USA. · Neurology. · Pubmed #17625107 No free full text.

Abstract: BACKGROUND: Patients with Parkinson disease (PD) often have cardiac sympathetic denervation and failure of neurocirculatory regulation by baroreflexes. Familial PD caused by mutation of the gene encoding alpha-synuclein or by alpha-synuclein gene triplication also features cardiac sympathetic denervation and baroreflex failure. METHODS: Here we report results of cardiac sympathetic neuroimaging by 6-[(18)F]fluorodopamine PET, baroreflex testing based on beat-to-beat hemodynamic responses to the Valsalva maneuver, and nigrostriatal neuroimaging using 6-[(18)F] fluorodopa PET in a proband with mutation of the gene encoding leucine-rich repeat kinase 2 (LRRK2), the most common genetic abnormality identified so far in familial PD. RESULTS: The patient had no detectable 6-[(18)F] fluorodopamine-derived radioactivity in the left ventricular myocardium, a progressive fall in blood pressure during the Valsalva maneuver and no pressure overshoot after release of the maneuver, and decreased 6-[(18)F] fluorodopa-derived radioactivity bilaterally in the putamen and substantia nigra. CONCLUSION: This patient with Parkinson disease (PD) caused by LRRK2 mutation had evidence of cardiac sympathetic denervation, baroreflex-sympathoneural and baroreflex-cardiovagal failure, and nigrostriatal dopamine deficiency, a pattern resembling that in the sporadic disease. The results fit with the concept that in LRRK2 PD, parkinsonism, cardiac sympathetic denervation, and baroreflex failure can result from a common pathogenetic process.

Scholz S, Mandel RJ, Fernandez HH, Foote KD, Rodriguez RL, Barton E, Munson S, Singleton A, Okun MS. · Molecular Genetics Unit, National Institute on Aging, National Institutes of Health, Bethsda, MD, USA. · Eur J Neurol. · Pubmed #17116211 No free full text.

Abstract: In the last decade, major breakthroughs in the understanding of genetic contributions to Parkinson's disease (PD) have been achieved. Recently, mutations in LRRK2, encoding dardarin, have been found to be responsible for an autosomal dominant parkinsonism (OMIM 607060). We screened 311 subjects (cases: n = 202, controls: n = 109) for the three previously reported LRRK2 mutations. Our investigation revealed a sporadic case of PD with a heterozygous mutation G2019S (c.6055G>A). Here, we present the clinical phenotype of this patient and discuss the implications of genetic testing for the G2019S mutation in patients with sporadic PD.

Fung HC, Scholz S, Matarin M, Simón-Sánchez J, Hernandez D, Britton A, Gibbs JR, Langefeld C, Stiegert ML, Schymick J, Okun MS, Mandel RJ, Fernandez HH, Foote KD, Rodríguez RL, Peckham E, De Vrieze FW, Gwinn-Hardy K, Hardy JA, Singleton A. · Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA. · Lancet Neurol. · Pubmed #17052657 No free full text.

Abstract: BACKGROUND: Several genes underlying rare monogenic forms of Parkinson's disease have been identified over the past decade. Despite evidence for a role for genetics in sporadic Parkinson's disease, few common genetic variants have been unequivocally linked to this disorder. We sought to identify any common genetic variability exerting a large effect in risk for Parkinson's disease in a population cohort and to produce publicly available genome-wide genotype data that can be openly mined by interested researchers and readily augmented by genotyping of additional repository subjects. METHODS: We did genome-wide, single-nucleotide-polymorphism (SNP) genotyping of publicly available samples from a cohort of Parkinson's disease patients (n=267) and neurologically normal controls (n=270). More than 408,000 unique SNPs were used from the Illumina Infinium I and HumanHap300 assays. FINDINGS: We have produced around 220 million genotypes in 537 participants. This raw genotype data has been and as such is the first publicly accessible high-density SNP data outside of the International HapMap Project. We also provide here the results of genotype and allele association tests. INTERPRETATION: We generated publicly available genotype data for Parkinson's disease patients and controls so that these data can be mined and augmented by other researchers to identify common genetic variability that results in minor and moderate risk for disease.

Guerreiro RJ, Bras JM, Santana I, Januario C, Santiago B, Morgadinho AS, Ribeiro MH, Hardy J, Singleton A, Oliveira C. · Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, USA. · BMC Neurol. · Pubmed #16824219 links to  free full text

Abstract: BACKGROUND: Pathological brain iron deposition has been implicated as a source of neurotoxic reactive oxygen species in Alzheimer (AD) and Parkinson diseases (PD). Iron metabolism is associated with the gene hemochromatosis (HFE Human genome nomenclature committee ID:4886), and mutations in HFE are a cause of the iron mismetabolism disease, hemochromatosis. Several reports have tested the association of HFE variants with neurodegenerative diseases, such as AD and PD with conflicting results. METHODS: Genotypes were analysed for the two most common variants of HFE in a series of 130 AD, 55 Mild Cognitive Impairment (MCI) and 132 PD patients. Additionally, a series of 115 healthy age-matched controls was also screened. RESULTS: A statistically significant association was found in the PD group when compared to controls, showing that the presence of the C282Y variant allele may confer higher risk for developing the disease. CONCLUSION: Taken together these results suggest that the common variants in HFE may be a risk factor for PD, but not for AD in the Portuguese population.

Greggio E, Jain S, Kingsbury A, Bandopadhyay R, Lewis P, Kaganovich A, van der Brug MP, Beilina A, Blackinton J, Thomas KJ, Ahmad R, Miller DW, Kesavapany S, Singleton A, Lees A, Harvey RJ, Harvey K, Cookson MR. · Cell Biology and Gene Expression Unit, Laboratory of Neurogenetics, National Institute on Aging, Bethesda, MD 20892-3707, USA. · Neurobiol Dis. · Pubmed #16750377 No free full text.

Abstract: Mutations in the LRRK2 gene, coding for dardarin, cause dominantly inherited Parkinson's disease (PD). Dardarin is a large protein, and mutations are found throughout the gene including the kinase domain. However, it is not clear if kinase activity is important for the damaging effects of pathogenic mutations. In this study, we noted two cellular phenotypes associated with mutant dardarin. First, pathogenic mutations increase the tendency of dardarin to form inclusion bodies. Secondly, neurons and neuronal cell lines undergo cell death after expression of mutant protein. Manipulating activity by replacing the kinase domain with a 'kinase-dead' version blocks inclusion body formation and strongly delays cell death. This predicts that kinase inhibitors will be useful therapeutic agents in patients with LRRK2 mutations and, perhaps, in sporadic PD. We also show that dardarin protein is expressed within human midbrain neurons and that C-terminal epitopes are also found in some Lewy bodies.

Fung HC, Chen CM, Hardy J, Hernandez D, Singleton A, Wu YR. · Laboratory of Neurogenetics, National Institute on Aging, Bethesda, Maryland, USA. · Mov Disord. · Pubmed #16511860 No free full text.

Abstract: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been shown to cause autosomal dominant and sporadic Parkinson's disease (PD). We report here the frequency of a common heterozygous mutation, 2877510G>A, which produces a glycine-to-serine amino acid substitution at codon 2019 in idiopathic Taiwanese PD. The extreme rarity of the G2019S mutation in our population suggests the occurrence of this mutation resulted from a common European founder.

Cookson MR, Xiromerisiou G, Singleton A. · Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20982-3707, USA. · Curr Opin Neurol. · Pubmed #16280683 No free full text.

Abstract: PURPOSE OF REVIEW: Rapid progress in genetics has meant that there are now five genes identified for 'Parkinson's disease'. The detailed phenotypes vary, but generally the dominant genes cause a Lewy body disease spectrum whereas recessive genes cause a milder parkinsonism with variable inclusion body pathology. The subject of this review is to highlight these discoveries and to discuss their relationships to idiopathic Parkinson's disease. RECENT FINDINGS: In January 2004, mutations in PINK1, coding for a mitochondrial kinase, were found to be causal for recessive parkinsonism. Subsequently, several studies have found additional mutations associated with early onset parkinsonism. Some cases have been described with a phenotype much closer to idiopathic Parkinson's disease, but it does not appear that PINK1 is a major risk factor for the sporadic disease. Later in the same year, the LRRK2 gene was shown to cause a dominant disease with a broader phenotype. The protein product was named dardarin and contains GTPase and kinase domains. Lewy bodies have been reported in LRRK2 cases, potentially linking this gene with sporadic Parkinson's disease. One mutation, G2019S, is found in a significant percentage of cases, including sporadic Parkinson's disease. SUMMARY: Mutations in these two genes, along with previously described Mendelian variants, are beginning to yield important information about loss of specific neuronal groups or to protein inclusion pathology. How this relates to sporadic Parkinson's disease, however, is not yet fully defined. There are clear phenotypic overlaps with genetic and sporadic Parkinson's disease, especially for the dominant genes, suggesting that common facets of pathogenesis may exist.

Eblan MJ, Nguyen J, Ziegler SG, Lwin A, Hanson M, Gallardo M, Weiser R, De Lucca M, Singleton A, Sidransky E. · No affiliation provided · Mov Disord. · Pubmed #16261622 No free full text.

This publication has no abstract.

Hadjigeorgiou GM, Xiromerisiou G, Gourbali V, Aggelakis K, Scarmeas N, Papadimitriou A, Singleton A. · Neurogenetics Unit, Department of Neurology, Medical School, University of Thessaly, Larissa, Greece. · Mov Disord. · Pubmed #16250025 No free full text.

Abstract: The alpha-synuclein Rep1 polymorphism was studied in patients and controls in an ethnic Greek population. There was an association of allele 2 with risk of Parkinson's disease (PD; adjusted odd ratio = 3.25; 95% CI = 1.80-5.87). Survival analyses (Cox proportional hazards models) were employed to explore the influence of genotypes on age at onset of PD. Age at onset of carriers of at least one Rep1 allele 2 was earlier (3.6 years) compared to noncarriers (adjusted hazard ratio = 2.21; 95% CI = 1.58-3.10). Kaplan-Meier analysis also supported a dosage effect of Rep1 allele 2 on age at onset. For Rep1 allele 1, there was neither association with risk of PD nor influence on age at onset. This is the first study showing an influence of Rep1 polymorphism on age at onset of PD.

Paisán-Ruíz C, Lang AE, Kawarai T, Sato C, Salehi-Rad S, Fisman GK, Al-Khairallah T, St George-Hyslop P, Singleton A, Rogaeva E. · National Institute on Aging, National Institutes of Health, Porter Neuroscience Research Center, Bethesda, MD, USA. · Neurology. · Pubmed #16157901 No free full text.

Abstract: BACKGROUND: In addition to the four well-confirmed genes linked to early-onset Parkinson disease (PD) (SNCA, PARKIN, DJ-1, and PINK1), mutations in the leucine-rich repeat kinase 2 gene (LRRK2) have recently been identified in families with autosomal dominant late-onset PD. OBJECTIVE: To perform mutation analysis of LRRK2 in probands of families showing dominant inheritance of PD and to conduct a case control association study to test the hypothesis that common coding variations might be associated with increased susceptibility to PD. METHODS: All 51 LRRK2 coding exons were sequenced in 23 probands and the mutation frequencies were evaluated in 180 neurologically normal control subjects. For the association study the authors genotyped four coding LRRK2 polymorphisms in 250 normal control subjects and 121 patients with PD (predominantly white patients of Canadian origin), 84% of whom had age at onset before 50 years and 42% had a positive family history. RESULTS: The authors identified three probands with heterozygous LRRK2 mutations: two of them have the known G2019S substitution and one proband has a novel I1371V substitution. Mutation analysis of a large family demonstrated complete segregation of the G2019S with PD. However, there was no association between PD and any of the four polymorphisms at the allelic or genotypic levels (p > 0.17). Furthermore, the authors did not detect a modifying effect for any genotype or of APOE genotypes upon the age at onset in the PD group (p > 0.20). CONCLUSIONS: The results support the prior suggestion that LRRK2 mutations cause PD. The disease in the families reported here presents a phenotype indistinguishable from typical PD. All three families demonstrate a very variable age at onset that is not explained by APOE genotypes. The common coding variations in the LRRK2 gene neither constitute strong PD risk factors nor modify the age at onset; however, the possibility of a modest risk effect remains to be assessed in large datasets.

Bras JM, Guerreiro RJ, Ribeiro MH, Januario C, Morgadinho A, Oliveira CR, Cunha L, Hardy J, Singleton A. · Neurology Service, Coimbra University Hospital, Coimbra, Portugal. · Mov Disord. · Pubmed #16149095 No free full text.

Abstract: LRRK2 mutations have recently been described in families with Parkinson's disease. Here we show that one of them (G2019S) is present in 6% (7 of 124) unrelated cases of disease in a clinic-based sample series from central Portugal, but not present in 126 controls from the same population. Thus, LRRK2 mutations appear to be a common cause of typical Parkinson's disease and as such will alter clinical practice.

Momeni P, Lu CS, Chou YH, Chang HC, Chen RS, Chen CC, Hsu JT, Singleton A, Hardy J. · Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, Maryland 20952, USA. · Mov Disord. · Pubmed #16078202 No free full text.

Abstract: We have assessed the haplotypes at the ATXN2 locus in Taiwanese controls and in individuals with SCA2 ataxia with both ataxic and parkinsonian features. Our intention was to determine whether a different ataxin 2 haplotypes predisposed to the two phenotypes. In fact, our analysis showed that all SCA2 mutations carriers had the same ataxin 2 haplotype: haplotype B, which accounts for only 15% of control haplotypes, implying that there is a common founder for all Taiwanese SCA2 patients.

Martinez M, Brice A, Vaughan JR, Zimprich A, Breteler MM, Meco G, Filla A, Farrer MJ, Bétard C, Singleton A, Hardy J, De Michele G, Bonifati V, Oostra BA, Gasser T, Wood NW, Dürr A. · INSERM EMI00-06, Evry, France. · Am J Med Genet B Neuropsychiatr Genet. · Pubmed #15924299 No free full text.

Abstract: Analysis of the apolipoprotein E genotype in sibpairs with Parkinson's disease showed the E4 allele was over represented in those who shared the adjacent chromosome 19 markers. This suggests that apolipoprotein E4 is responsible for the linkage peak in this region and that it is a modest risk factor for Parkinson's disease.