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1.  A novel de novo pathogenic mutation in CACNA1A gene 
doi:10.1002/mds.25198
PMCID: PMC3477248  PMID: 23038654
episodic ataxia type 2; CACNA1A; p.R1346Stop; acetazolamide; cerebellar vermis
2.  LRRK2 variation and Parkinson's disease in African Americans 
The global impact of LRRK2 mutations is yet to be realized with a lack of studies in specific ethnic groups, including those of Asian and African descent. Herein we investigated the frequency of common LRRK2 variants by complete exon sequencing in a series of publicly available African American Parkinson's disease patients. Our study identified three novel synonymous exonic variants and thirteen known coding variations however, there did not appear to be any frequent (>5%) pathogenic mutations. Given the ethnic-specific LRRK2 variation previously identified in PD further studies in under-represented populations are warranted.
doi:10.1002/mds.23163
PMCID: PMC2939165  PMID: 20669299
Parkinsonism; Leucine-rich repeat kinase 2; genetics
3.  Three families with Perry syndrome from distinct parts of the world 
Parkinsonism & related disorders  2014;20(8):884-888.
Objectives
Perry syndrome consists of autosomal dominant Parkinsonism, depression, weight loss, and central hypoventilation. Eight mutations in 16 families have been reported: p.F52L, p.G67D, p.G71R, p.G71E, p.G71A, p.T72P, p.Q74P, and p.Y78C located in exon 2 of the dynactin 1 (DCTN1) gene on chromosome 2p13.1.
Methods
Genealogical, clinical, genetic, and functional studies were performed in three kindreds from New Zealand, the United States, and Colombia. A diaphragmatic pacemaker was implanted in the proband from the Colombian family to treat her respiratory insufficiency. Dopaminergic therapy was initiated in probands from two families.
Results
Besides the probands, 17 symptomatic relatives from all families were identified. The cardinal signs of Perry syndrome were present in all three probands with symptomatic disease onset in their fifth or sixth decade of life. Parkinsonism was moderate with a partial response to dopaminergic treatment. All affected persons but two died of respiratory insufficiency. The proband from the Colombian family is alive most likely due to early diagnosis and implantation of a diaphragmatic pacemaker. Two-and-a-half-year follow-up examination has revealed that the diaphragmatic pacemaker is optimally functioning without any major complications. In the Colombian and US families, the DCTN1 p.G71R and in the New Zealand family the DCTN1 p.Y78C mutations were identified. In functional assays, both mutations altered microtubule binding consistent with a pathogenic role.
Conclusions
Perry syndrome is a rare condition, but new cases are expected to be diagnosed worldwide. Early diagnosis prevents life-threatening acute respiratory failure. Diaphragmatic pacemakers should be considered as an effective symptomatic treatment option.
doi:10.1016/j.parkreldis.2014.05.004
PMCID: PMC4125456  PMID: 24881494
4.  ALS-FTD complex disorder due to C9ORF72 gene mutation – description of first Polish family 
European neurology  2014;72(0):64-71.
Background
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are complex neurodegenerative disorders that can be either sporadic or familial and can overlap clinically and pathologically. We present the first Central-Eastern European family with ALS-FTD syndrome due to a C9ORF72 repeat expansion.
Methods
We studied a family consisting of 37 family members, and six of these family members were genetically evaluated for C9ORF72 expansions. Family members were evaluated clinically, by history, and by chart review.
Results
Five generations of the family were studied, and six affected family members were identified. All affected members were females and had a different clinical presentation, which was either ALS, FTD, or both. Among genetically evaluated subjects, five carried a C9ORF72 expansion; four of these individuals remain clinically unaffected.
Conclusion
Our report reveals that the hexanucleotide repeat expansion of C9ORF72, which is the most common genetic cause of ALS-FTD complex disorder, is also present in Central-Eastern Europe. Further studies are needed to assess the frequency of this expansion in the Polish population with familial as well as sporadic ALS, FTD, and the ALS-FTD complex disorder.
doi:10.1159/000362267
PMCID: PMC4111969  PMID: 24861139
ALS-FTD complex disorder; familial ALS-FTD; C9ORF72 gene mutation; phenotype
5.  DCTN1 mutation analysis in families with progressive supranuclear palsy-like phenotype 
JAMA neurology  2014;71(2):208-215.
doi:10.1001/jamaneurol.2013.5100
PMCID: PMC4169198  PMID: 24343258
6.  Update on novel familial forms of Parkinson’s disease and multiple system atrophy 
Parkinsonism & related disorders  2014;20(0 1):S29-S34.
Parkinson’s disease (PD) and multiple system atrophy (MSA) are progressive neurodegenerative disorders classified as synucleinopathies, which are defined by the presence of α-synuclein protein pathology. Genetic studies have identified a total of 18 PARK loci that are associated with PD. The SNCA gene encodes the α-synuclein protein. The first pathogenic α-synuclein p.A53T substitution was discovered in 1997; this was followed by the identification of p.A30P and p.E46K pathogenic substitutions in 1998 and 2004, respectively. In the last year, two possible α-synuclein pathogenic substitutions, p.A18T and p.A29S, and two probable pathogenic substitutions, p.H50Q and p.G51D have been nominated. Next-generation sequencing approaches in familial PD have identified mutations in the VPS35 gene. A VPS35 p.D620N substitution remains the only confirmed pathogenic substitution. A second synucleinopathy, MSA, originally was considered a sporadic condition with little or no familial aggregation. However, recessive COQ2 mutations recently were nominated to be the genetic cause in a subset of familial and sporadic MSA cases. Further studies on the clinicogenetics and pathology of parkinsonian disorders will facilitate clarification of the molecular characteristics and pathomechanisms underlying these disorders.
doi:10.1016/S1353-8020(13)70010-5
PMCID: PMC4215194  PMID: 24262183
SNCA; VPS35; PD; MSA; Genetics; Familial
7.  An adult-onset leukoencephalopathy with axonal spheroids and pigmented glia accompanied by brain calcifications 
Journal of neurology  2013;260(10):10.1007/s00415-013-7093-x.
doi:10.1007/s00415-013-7093-x
PMCID: PMC3865925  PMID: 24036850
adult-onset leukoencephalopathy with axonal spheroids and pigmented glia; CSF1R; calcification; computed tomography; white matter; differential diagnosis
8.  Parkinsonian features in hereditary diffuse leukoencephalopathy with spheroids (HDLS) and CSF1R mutations 
Parkinsonism & related disorders  2013;19(10):869-877.
Atypical Parkinsonism associated with white matter pathology has been described in cerebrovascular diseases, mitochondrial cytopathies, osmotic demyelinating disorders, leukoencephalopathies including leukodystrophies, and others. Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an autosomal dominant disorder with symptomatic onset in midlife and death within a few years after symptom onset. Neuroimaging reveals cerebral white matter lesions that are pathologically characterized by non-inflammatory myelin loss, reactive astrocytosis, and axonal spheroids. Most cases are caused by mutations in the colony-stimulating factor 1 receptor (CSF1R) gene.
We studied neuropathologically verified HDLS patients with CSF1R mutations to assess Parkinsonian features. Ten families were evaluated with 16 affected individuals. During the course of the illness, all patients had at least some degree of bradykinesia. Fifteen patients had postural instability, and seven had rigidity. Two patients initially presented with Parkinsonian gait and asymmetrical bradykinesia. These two patients and two others exhibited bradykinesia, rigidity, postural instability, and tremor (two with resting) early in the course of the illness. Levodopa/carbidopa therapy in these four patients provided no benefit, and the remaining 12 patients were not treated. The mean age of onset for all patients was about 45 years (range, 18-71) and the mean disease duration was approximately six years (range, 3-11).
We also reviewed HDLS patients published prior to the CSF1R discovery for the presence of Parkinsonian features. Out of 50 patients, 37 had gait impairments, 8 rigidity, 7 bradykinesia, and 5 resting tremor. Our report emphasizes the presence of atypical Parkinsonism in HDLS due to CSF1R mutations.
doi:10.1016/j.parkreldis.2013.05.013
PMCID: PMC3977389  PMID: 23787135
HDLS; CSF1R mutation; Parkinsonism; Autosomal dominant; White matter disorders
9.  Update on Genetics of Parkinsonism 
Neuro-Degenerative Diseases  2012;10(1-4):257-260.
Background
Major progress in genetic studies of Parkinson's disease (PD) and parkinsonism has been achieved in the last two decades. Objective: We provide a brief review of the current status of PARK and non-PARK loci/genes, and discuss two new genes: eIF4G1 and VPS35.
Methods
The literature on PARK and non-PARK loci/genes was reviewed and some novel information on two new genes is provided.
Results
There are 18 PARK loci. The symptomatic carriers of these genes usually present with parkinsonism, although additional clinical features can be seen during the course of the disease. Carriers of non-PARK loci/genes frequently present with a mixed phenotype that includes parkinsonism and additional clinical features. Carriers of the eIF4G1 and VPS35 genes present with a parkinsonian phenotype. The pathology of eIF4G1 is of the α-synuclein type; the pathology of VPS35 is unknown.
Conclusion
The current genetic classification of PD/parkinsonism genes is not ideal. The pathological classification based on the accumulation of particular proteins/inclusions is also misleading since there are kindred with a single mutation but pleomorphic pathology. A better classification of neurodegenerative conditions is needed. It is hoped that the genetic studies will lead to better therapies.
doi:10.1159/000334285
PMCID: PMC3363351  PMID: 22261420
Genetics; Parkinsonism; SNCA; PRKN; LRRK2; GBA; eIF4G1; VPS35
10.  Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS): a misdiagnosed disease entity 
Journal of the Neurological Sciences  2011;314(1-2):130-137.
Hereditary diffuse leukoencephalopathy with spheroids (HDLS) was originally described in a large Swedish pedigree. Since then, 22 reports describing a total of 13 kindred's and 11 sporadic cases have been published. Inheritance is autosomal dominant, albeit the gene is unknown. Here we report on the clinical findings, genealogical data, brain MRI data, and autopsy/biopsy findings of four probands from three independently ascertained novel families from Norway, Germany and US.
We identified a 39-year-old female and her twin sister, a 52-year-old male and a 47-year-old male with progressive neurological illness characterized by personality changes, cognitive decline and motor impairments, such as gait problems, bradykinesia, tremor and rigidity. Brain MRI showed white matter abnormalities with frontal prominence. Brain biopsy/autopsies were consistent with HDLS.
HDLS is an under-recognized disease and in reporting these cases, we aim to increase the awareness of the disorder. Due to varied and wide phenotypic presentations, which may imitate several neurodegenerative diseases, HDLS can be difficult to diagnose. Definitive diagnosis can be established only by direct brain tissue examination. Familiarity with the clinical presentation and typical neuroimaging findings may be helpful in narrowing the diagnosis.
doi:10.1016/j.jns.2011.10.006
PMCID: PMC3275663  PMID: 22050953
HDLS; White matter disease; Autosomal dominant; Personality changes; Cognitive problems; Depression; Parkinsonism
11.  An African-American Family with Dystonia 
Parkinsonism & related disorders  2011;17(7):547-550.
The genetic cause of late-onset focal and segmental dystonia remains unknown in most individuals. Recently, mutations in Thanatos-associated protein domain containing, apoptosis associated protein 1 (THAP1) have been described in DYT6 dystonia and associated with some cases of familial and sporadic late-onset dystonia in Caucasians. We are not aware of any previous descriptions of familial dystonia in African Americans or reports of THAP1 mutations in African Americans. Herein, we characterize an African-American (AA) kindred with late-onset primary dystonia, clinically and genetically. The clinical phenotype included cervical, laryngeal and hand-forearm dystonia. Symptoms were severe and disabling for several family members, whereas others only displayed mild signs. There were no accompanying motor or cognitive signs. In this kindred, age of onset ranged from 45 to 50 years and onset was frequently sudden, with symptoms developing within weeks or months. DYT1 was excluded as the cause of dystonia in this kindred. The entire genomic region of THAP1, including non-coding regions, was sequenced. We identified 13 sequence variants in THAP1, although none co-segregated with dystonia. A novel THAP1 variant (c.-237-3G>T/A) was found in 3/84 AA dystonia patient alleles and 3/212 AA control alleles, but not in 5,870 Caucasian alleles. In summary, although previously unreported, familial primary dystonia does occur in African Americans. Genetic analysis of the entire genomic region of THAP1 revealed a novel variant that was specific for African Americans. Therefore, genetic testing for dystonia and future studies of candidate genes must take genetic background into consideration.
doi:10.1016/j.parkreldis.2011.04.019
PMCID: PMC3137742  PMID: 21601506
Dystonia; Genetics; African American; DYT6; THAP1; Adult-Onset Dystonias; Dystonia, Hereditary; Focal Dystonia
12.  Leucine-Rich Repeat Kinase 2 Gene-Associated Disease: Redefining Genotype-Phenotype Correlation 
Neuro-Degenerative Diseases  2010;7(1-3):175-179.
Background
Leucine-rich repeat kinase 2 (LRRK2) has emerged as the most prevalent genetic cause of Parkinson's disease (PD) among Caucasians. Patients carrying an LRRK2 mutation display significant variability of clinical and pathologic phenotypes across and within affected families.
Methods
Herein, we review available clinical and pathologic data on patients with an LRRK2 mutation who have come to autopsy.
Results
Thirty-eight patients have been reported who presented clinically with PD; parkinsonism with resistance to levodopa, supranuclear gaze palsy, or autonomic dysfunction; or tremor and dementia. Pathology showed typical PD-type Lewy body disease (LBD) in most patients, whereas in others there was ‘pure’ nigral degeneration (one with TDP-43-positive inclusions), diffuse LBD, or tau-, α-synuclein- or ubiquitin-positive pathology reminiscent of progressive supranuclear gaze palsy, multisystem atrophy, and frontotemporal dementia with ubiquitin-positive inclusions.
Conclusions
Such clinical and pathologic variability suggests Lrrk2 acts upstream from other proteins implicated in neurodegeneration. Specific mutations may be associated with alternative progressive supranuclear gaze palsy-like or ‘pure’ nigral degeneration phenotypes. A different effect on Lrrk2 kinase activity may play a role in such heterogeneity.
doi:10.1159/000289232
PMCID: PMC2859237  PMID: 20197701
Leucine-rich repeat kinase 2gene; Parkinson's disease; Lewy body disease; Progressive supranuclear gaze palsy; Nigral degeneration
13.  Elucidating the genetics and pathology of Perry syndrome 
Perry syndrome is characterized clinically by autosomal dominantly inherited, rapidly progressive parkinsonism, depression, weight loss and hypoventilation. In the seven families reported previously and the two new families presented herein (the Hawaii family and the Fukuoka-4 Japanese family), the mean disease onset age is 48 years (range: 35-61) and the mean disease duration five years (range: 2-10). Histology and immunohistochemistry show severe neuronal loss in the substantia nigra and locus coeruleus, with TDP-43-positive pathology in neurons (intranuclear and cytoplasmic inclusions, dystrophic neurites, axonal spheroids) and glial cells (glial cytoplasmic inclusions). Compared with other TDP-43-proteinopathies (amyotrophic lateral sclerosis and ubiquitin-positive frontotemporal lobar degeneration), the distribution is unique in Perry syndrome with pallidonigral distribution and sparing of the cortex, hippocampus and motor neurons. The genetic cause of Perry syndrome was recently identified with five mutations in the dynactin gene (DCTN1) segregating with disease in eight families. DCTN1 encodes p150glued, the major subunit of the dynactin protein complex, which plays a crucial role in retrograde axonal and cytoplasmic transport of various cargoes. Evidence suggests the Perry mutations alter the binding of p150glued to microtubules. Further studies will examine reasons for the vulnerability of selected neuronal populations in Perry syndrome, and the link between the genetic defect and TDP-43 pathology.
doi:10.1016/j.jns.2009.08.044
PMCID: PMC2813334  PMID: 19732908
Perry syndrome; parkinsonism; depression; hypoventilation; dynactin; DCTN1; p150glued; TDP-43
14.  Familial idiopathic basal ganglia calcification: a challenging clinical-pathological correlation 
Journal of neurology  2009;256(5):839-842.
doi:10.1007/s00415-009-5025-6
PMCID: PMC2875477  PMID: 19252803
Fahr disease; brain calcinosis; idiopathic basal ganglia calcification
15.  Clinical and Genetic Description of a Family With a High Prevalence of Autosomal Dominant Restless Legs Syndrome 
Mayo Clinic Proceedings  2009;84(2):134-138.
OBJECTIVE: To conduct clinical and molecular genetic analyses of the members of an extended family in Central Indiana with a high prevalence of restless legs syndrome (RLS).
PARTICIPANTS AND METHODS: From February 1, 2006, through August 31, 2008, we collected data from members of this family, which is of English descent. Genealogical methods were used to expand the family tree, and family members were screened with an RLS questionnaire. Telephone interviews and personal examinations were performed at Mayo Clinic and during a field trip to Central Indiana. Blood samples were collected for molecular genetic analysis. A follow-up telephone interview was conducted 1 year later.
RESULTS: The family tree spans 7 generations with 88 living members, 30 of whom meet the criteria for diagnosis of RLS established by the International Restless Legs Syndrome Study Group. Three affected family members also have Parkinson disease or essential tremor. The mode of RLS inheritance is compatible with an autosomal dominant pattern. The affected family members do not exhibit linkage to the 5 known RLS loci or mutations in the RLS susceptibility genes MEIS1 and BTBD9.
CONCLUSION: Of 88 members of this single extended family in Central Indiana, 30 were diagnosed as having RLS. Because our analysis shows that the disease is not linked to any of the known RLS loci or risk-associated genes, we postulate that members of this family may carry a gene mutation in a novel genetic locus.
Of 88 members of a single extended family, 30 were diagnosed as having restless legs syndrome; because this analysis shows that the disease is not linked to any of the known restless legs syndrome loci or risk-associated genes, members of this family may carry a gene mutation in a novel genetic locus.
PMCID: PMC2664577  PMID: 19181647
16.  Etiology and Pathophysiology of Frontotemporal Dementia, Parkinson Disease and Alzheimer Disease: Lessons from Genetic Studies 
Neuro-Degenerative Diseases  2008;5(3-4):122-125.
Genetic studies have led to major discoveries in the pathogenesis of various neurodegenerative diseases. Ubiquitin-positive familial frontotemporal dementia was recently found to be caused by mutations in the progranulin gene (PGRN), and the major constituent of the inclusions, TDP-43, was subsequently identified. The tau gene (MAPT) causes frontotemporal dementia with parkinsonism linked to chromosome 17. In Parkinson disease, LRRK2 mutations have emerged as a major cause of both familial and sporadic forms, adding to the previously known genes SNCA, PRKN, DJ1 and PINK1. Several genes have been implicated in Alzheimer disease, including the APP gene and the PSEN genes. Recently, variants in the sortilin-related receptor 1 gene, SORL1, were associated with Alzheimer disease.
doi:10.1159/000113680
PMCID: PMC2826449  PMID: 18322368
Alzheimer disease; Dementia; Frontotemporal dementia; Frontotemporal lobar degeneration; Neurodegeneration; Parkinson disease
17.  Genetic variation of the retromer subunits VPS26A/B-VPS29 in Parkinson’s disease 
Neurobiology of aging  2014;35(8):1958.e1-1958.e2.
We recently showed that mutation of the VPS35 gene can cause late-onset Parkinson’s disease. In the present study we sequenced 702 affected subjects from the Mayo Clinic Parkinson’s disease patient-control series for the VPS29 and VPS26A/B genes. We identified only two rare non-synonymous variants in the VPS26A p.K93E and VPS29 p.N72H. The results show that mutations in the genes composing the retromer cargo recognition subunit are not a common cause of Parkinson’s disease.
doi:10.1016/j.neurobiolaging.2014.03.004
PMCID: PMC4023811  PMID: 24684791
Genetics; Parkinson's disease/Parkinsonism; Retromer; VPS35
18.  In vivo dopaminergic and serotonergic dysfunction in DCTN1 gene mutation carriers 
Introduction
We have used positron emission tomography (PET) to assess dopaminergic and serotonergic terminal density in three subjects carrying a mutation in the DCT1 gene, two clinically affected with Perry syndrome.
Methods
All subjects had brain imaging using 18F-6-fluoro-L-dopa (FDOPA, dopamine synthesis and storage), (+)-11C-dihydrotetrabenazine (DTBZ, vesicular monoamine transporter type 2), and 11C-raclopride (RAC, dopamine D2/D3 receptors). One subject also underwent PET with 11C-3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile (DASB, serotonin transporter).
Results
FDOPA-PET and DTBZ-PET in the affected individuals showed a reduction of striatal tracer uptake. Also, RAC-PET showed higher uptake in these area. DASB-PET showed significant uptake changes in left orbitofrontal cortex, bilateral anterior insula, left dorsolateral prefrontal cortex, left orbitofrontal cortex, left posterior cingulate cortex, left caudate and left ventral striatum.
Conclusions
Our data showed evidence of both striatal dopaminergic and widespread cortical/subcortical serotonergic dysfunctions in individuals carrying a mutation in the DCTN1 gene.
doi:10.1002/mds.25893
PMCID: PMC4139463  PMID: 24797316
Perry syndrome; dynactin gene; positron emission tomography; dopaminergic dysfunction; serotonergic dysfunction
19.  Genetic screening and functional characterization of PDGFRB mutations associated with Basal Ganglia Calcification of Unknown Etiology 
Human mutation  2014;35(8):964-971.
Three causal genes for Idiopathic Basal Ganglia Calcification (IBGC) have been identified. Most recently, mutations in PDGFRB, encoding a member of the platelet-derived growth factor receptor family type β, and PDGFB, encoding PDGF-B, the specific ligand of PDGFRβ, were found implicating the PDGF-B/PDGFRβ pathway in abnormal brain calcification. In this study we aimed to identify and study mutations in PDGFRB and PDGFB in a series of 26 patients from the Mayo Clinic Florida Brain Bank with moderate to severe basal ganglia calcification (BCG) of unknown etiology. No mutations in PDGFB were found. However, we identified one mutation in PDGFRB, p.R695C located in the tyrosine kinase domain, in one BGC patient. We further studied the function of p.R695C mutant PDGFRβ and two previously reported mutants, p.L658P and p.R987W PDGFRβ in cell culture. We show that, in response to PDGF-BB stimulation, the p.L658P mutation completely suppresses PDGFRβ autophosphorylation whereas the p.R695C mutation results in partial loss of autophosphorylation. For the p.R987W mutation, our data suggest a different mechanism involving reduced protein levels. These genetic and functional studies provide the first insight into the pathogenic mechanisms associated with PDGFRB mutations and provide further support for a pathogenic role of PDGFRB mutations in BGC.
doi:10.1002/humu.22582
PMCID: PMC4107018  PMID: 24796542
Basal Ganglia Calcification; BGC; IBGC; Fahr disease; PDGFRB; PDGFB
20.  Genome-wide association study of corticobasal degeneration identifies risk variants shared with progressive supranuclear palsy 
Nature Communications  2015;6:7247.
Corticobasal degeneration (CBD) is a neurodegenerative disorder affecting movement and cognition, definitively diagnosed only at autopsy. Here, we conduct a genome-wide association study (GWAS) in CBD cases (n=152) and 3,311 controls, and 67 CBD cases and 439 controls in a replication stage. Associations with meta-analysis were 17q21 at MAPT (P=1.42 × 10−12), 8p12 at lnc-KIF13B-1, a long non-coding RNA (rs643472; P=3.41 × 10−8), and 2p22 at SOS1 (rs963731; P=1.76 × 10−7). Testing for association of CBD with top progressive supranuclear palsy (PSP) GWAS single-nucleotide polymorphisms (SNPs) identified associations at MOBP (3p22; rs1768208; P=2.07 × 10−7) and MAPT H1c (17q21; rs242557; P=7.91 × 10−6). We previously reported SNP/transcript level associations with rs8070723/MAPT, rs242557/MAPT, and rs1768208/MOBP and herein identified association with rs963731/SOS1. We identify new CBD susceptibility loci and show that CBD and PSP share a genetic risk factor other than MAPT at 3p22 MOBP (myelin-associated oligodendrocyte basic protein).
Corticobasal degeneration is a rare neurodegenerative disorder that can only be definitively diagnosed by autopsy. Here, Kouri et al. conduct a genome-wide-association study and identify two genetic susceptibility loci 17q21 (MAPT) and 3p12 (MOBP), and a novel susceptibility locus at 8p12.
doi:10.1038/ncomms8247
PMCID: PMC4469997  PMID: 26077951
21.  Alpha-synuclein REP1 variants and survival in Parkinson’s disease 
Objectives
To determine if alpha-synuclein REP1 genotypes are associated with survival in Parkinson’s disease.
Methods
Investigators from the Genetic Epidemiology of Parkinson’s Disease Consortium provided REP1 genotypes and baseline and follow-up clinical data for cases. The primary outcome was time to death. Cox proportional hazards regression models were used to assess the association of REP1 genotypes with survival.
Results
Twenty-one sites contributed data for 6,154 cases. There was no significant association between alpha-synuclein REP1 genotypes and survival in Parkinson’s disease. However, there was a significant association between REP1 genotypes and age at onset of PD (Hazard Ratio = 1.06, 95% Confidence Interval = 1.01–1.10, p value = 0.01).
Conclusions
In our large consortium study, alpha-synuclein REP1 genotypes were not associated with survival in Parkinson’s disease. Further studies of α–synuclein’s role in disease progression and long-term outcomes are needed.
doi:10.1002/mds.25841
PMCID: PMC4172351  PMID: 24578302
Parkinson’s disease; α-synuclein; gene; survival; association
22.  Exonic Re-Sequencing of the Chromosome 2q24.3 Parkinson’s Disease Locus 
PLoS ONE  2015;10(6):e0128586.
Genome-wide association studies (GWAS) in Parkinson’s disease (PD) have identified over 20 genomic regions associated with disease risk. Many of these loci include several candidate genes making it difficult to pinpoint the causal gene. The locus on chromosome 2q24.3 encompasses three genes: B3GALT1, STK39, and CERS6. In order to identify if the causal variants are simple missense changes, we sequenced all 31 exons of these three genes in 187 patients with PD. We identified 13 exonic variants including four non-synonymous and three insertion/deletion variants (indels). These non-synonymous variants and rs2102808, the GWAS tag SNP, were genotyped in three independent series consisting of a total of 1976 patients and 1596 controls. Our results show that the seven identified 2q24.3 coding variants are not independently responsible for the GWAS association signal at the locus; however, there is a haplotype, which contains both rs2102808 and a STK39 exon 1 6bp indel variant, that is significantly associated with PD risk (Odds Ratio [OR] = 1.35, 95% CI: 1.11–1.64, P = 0.003). This haplotype is more associated than each of the two variants independently (OR = 1.23, P = 0.005 and 1.10, P = 0.10, respectively). Our findings suggest that the risk variant is likely located in a non-coding region. Additional sequencing of the locus including promoter and regulatory regions will be needed to pinpoint the association at this locus that leads to an increased risk to PD.
doi:10.1371/journal.pone.0128586
PMCID: PMC4474914  PMID: 26090850
23.  Thiol peroxidases ameliorate LRRK2 mutant-induced mitochondrial and dopaminergic neuronal degeneration in Drosophila 
Human Molecular Genetics  2014;23(12):3157-3165.
Mutations in leucine-rich repeat kinase 2 (LRRK2) are common causes of familial Parkinson's disease (PD). LRRK2 has been shown to bind peroxiredoxin-3 (PRDX3), the most important scavenger of hydrogen peroxide in the mitochondria, in vitro. Here, we examined the interactions of LRRK2 and PRDX3 in Drosophila models by crossing transgenic LRRK2 and PRDX3 flies. As proof of principle experiments, we subsequently challenged LRRK2 and LRRK2/PRDX3 flies with a peroxidase mimic, Ebselen. We demonstrated that co-expression of PRDX3 with the LRRK2 kinase mutant G2019S in bigenic Drosophila ameliorated the G2019S mutant-induced reduction in peroxidase capacity, loss of dopaminergic neurons, shortened lifespan and mitochondrial defects of flight muscles in monogenic flies expressing the G2019S alone. Challenges with Ebselen recapitulated similar rescue of these phenotypic features in mutant-expressing Drosophila. The peroxidase mimic preserved neuronal and mitochondrial and neuronal integrity and improved mobility and survival in mutant-expressing Drosophila. Taken together, our study provides the first in vivo evidence to suggest that phosphoinhibition of endogenous peroxidases could be a mechanism in LRRK2-induced oxidant-mediated neurotoxicity. Our therapeutic experiments also highlight the potential of thiol peroxidases as neuroprotective agents in PD patients carrying LRRK2 mutations.
doi:10.1093/hmg/ddu026
PMCID: PMC4030771  PMID: 24459295
24.  Clinical Correlations With Lewy Body Pathology in LRRK2-Related Parkinson Disease 
JAMA neurology  2015;72(1):100-105.
IMPORTANCE
Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of genetic Parkinson disease (PD) known to date. The clinical features of manifesting LRRK2 mutation carriers are generally indistinguishable from those of patients with sporadic PD. However, some PD cases associated with LRRK2 mutations lack Lewy bodies (LBs), a neuropathological hallmark of PD. We investigated whether the presence or absence of LBs correlates with different clinical features in LRRK2-related PD.
OBSERVATIONS
We describe genetic, clinical, and neuropathological findings of 37 cases of LRRK2-related PD including 33 published and 4 unpublished cases through October 2013. Among the different mutations, the LRRK2 p.G2019S mutation was most frequently associated with LB pathology. Nonmotor features of cognitive impairment/dementia, anxiety, and orthostatic hypotension were correlated with the presence of LBs. In contrast, a primarily motor phenotype was associated with a lack of LBs.
CONCLUSIONS AND RELEVANCE
To our knowledge, this is the first report of clinicopathological correlations in a series of LRRK2-related PD cases. Findings from this selected group of patients with PD demonstrated that parkinsonian motor features can occur in the absence of LBs. However, LB pathology in LRRK2-related PD may be a marker for a broader parkinsonian symptom complex including cognitive impairment.
doi:10.1001/jamaneurol.2014.2704
PMCID: PMC4399368  PMID: 25401511
25.  Ribosomal protein s15 phosphorylation mediates LRRK2 neurodegeneration in Parkinson's disease 
Cell  2014;157(2):472-485.
Summary
Mutations in leucine-rich repeat kinase 2 (LRRK2) are a common cause of familial and sporadic Parkinson's disease (PD). Elevated LRRK2 kinase activity and neurodegeneration are linked, but the phosphosubstrate that connects LRRK2 kinase activity to neurodegeneration is not known. Here, we show that ribosomal protein s15 is a key pathogenic LRRK2 substrate in Drosophila and human neuron PD models. Phospho-deficient s15 carrying a threonine 136 to alanine substitution rescues dopamine neuron degeneration and age-related locomotor deficits in G2019S LRRK2 transgenic Drosophila and substantially reduces G2019S LRRK2-mediated neurite loss and cell death in human dopamine and cortical neurons. Remarkably, pathogenic LRRK2 stimulates both cap-dependent and cap-independent mRNA translation, and induces a bulk increase in protein synthesis in Drosophila, which can be prevented by phospho-deficient T136A s15. These results reveal a novel mechanism of PD pathogenesis linked to elevated LRRK2 kinase activity and aberrant protein synthesis in vivo.
doi:10.1016/j.cell.2014.01.064
PMCID: PMC4040530  PMID: 24725412

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