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See detailMutations in the phospholipid remodeling gene SERAC1 impair mitochondrial function and intracellular cholesterol trafficking and cause dystonia and deafness.
Wortmann, Saskia B.; Vaz, Frederic M.; Gardeitchik, Thatjana et al

in Nature genetics (2012), 44(7), 797-802

Using exome sequencing, we identify SERAC1 mutations as the cause of MEGDEL syndrome, a recessive disorder of dystonia and deafness with Leigh-like syndrome, impaired oxidative phosphorylation and 3 ... [more ▼]

Using exome sequencing, we identify SERAC1 mutations as the cause of MEGDEL syndrome, a recessive disorder of dystonia and deafness with Leigh-like syndrome, impaired oxidative phosphorylation and 3-methylglutaconic aciduria. We localized SERAC1 at the interface between the mitochondria and the endoplasmic reticulum in the mitochondria-associated membrane fraction that is essential for phospholipid exchange. A phospholipid analysis in patient fibroblasts showed elevated concentrations of phosphatidylglycerol-34:1 (where the species nomenclature denotes the number of carbon atoms in the two acyl chains:number of double bonds in the two acyl groups) and decreased concentrations of phosphatidylglycerol-36:1 species, resulting in an altered cardiolipin subspecies composition. We also detected low concentrations of bis(monoacyl-glycerol)-phosphate, leading to the accumulation of free cholesterol, as shown by abnormal filipin staining. Complementation of patient fibroblasts with wild-type human SERAC1 by lentiviral infection led to a decrease and partial normalization of the mean ratio of phosphatidylglycerol-34:1 to phosphatidylglycerol-36:1. Our data identify SERAC1 as a key player in the phosphatidylglycerol remodeling that is essential for both mitochondrial function and intracellular cholesterol trafficking. [less ▲]

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See detailGenetics of Parkinson's disease.
Kumar, Kishore R.; Djarmati-Westenberger, Ana; Grünewald, Anne UL

in Seminars in neurology (2011), 31(5), 433-40

The identification of genes contributing to Parkinson's disease (PD) has allowed for an improved understanding of the underlying pathogenesis of the disorder. The authors review the rapidly growing field ... [more ▼]

The identification of genes contributing to Parkinson's disease (PD) has allowed for an improved understanding of the underlying pathogenesis of the disorder. The authors review the rapidly growing field of PD genetics, with a focus on the clinical, genetic, and pathophysiologic features of well-validated monogenic forms of PD caused by mutations in the SNCA, LRRK2, PARKIN, PINK1, DJ-1, and ATP13A2 genes. In addition, they discuss mutations in the GBA gene, which increase susceptibility for PD. The authors also evaluate the implications of genome-wide association studies and stem cell-derived disease models and give recommendations for genetic testing. [less ▲]

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See detailMutations in PINK1 and Parkin impair ubiquitination of Mitofusins in human fibroblasts.
Rakovic, Aleksandar; Grünewald, Anne UL; Kottwitz, Jan et al

in PloS one (2011), 6(3), 16746

PINK1 and Parkin mutations cause recessive Parkinson's disease (PD). In Drosophila and SH-SY5Y cells, Parkin is recruited by PINK1 to damaged mitochondria, where it ubiquitinates Mitofusins and ... [more ▼]

PINK1 and Parkin mutations cause recessive Parkinson's disease (PD). In Drosophila and SH-SY5Y cells, Parkin is recruited by PINK1 to damaged mitochondria, where it ubiquitinates Mitofusins and consequently promotes mitochondrial fission and mitophagy.Here, we investigated the impact of mutations in endogenous PINK1 and Parkin on the ubiquitination of mitochondrial fusion and fission factors and the mitochondrial network structure. Treating control fibroblasts with mitochondrial membrane potential (Deltapsi) inhibitors or H(2)O(2) resulted in ubiquitination of Mfn1/2 but not of OPA1 or Fis1. Ubiquitination of Mitofusins through the PINK1/Parkin pathway was observed within 1 h of treatment. Upon combined inhibition of Deltapsi and the ubiquitin proteasome system (UPS), no ubiquitination of Mitofusins was detected. Regarding morphological changes, we observed a trend towards increased mitochondrial branching in PD patient cells upon mitochondrial stress.For the first time in PD patient-derived cells, we demonstrate that mutations in PINK1 and Parkin impair ubiquitination of Mitofusins. In the presence of UPS inhibitors, ubiquitinated Mitofusin is deubiquitinated by the UPS but not degraded, suggesting that the UPS is involved in Mitofusin degradation. [less ▲]

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See detailBioenergetic consequences of PINK1 mutations in Parkinson disease.
Abramov, Andrey Yurevich; Gegg, Matthew; Grünewald, Anne UL et al

in PloS one (2011), 6(10), 25622

BACKGROUND: Mutations of the gene for PTEN-induced kinase 1 (PINK1) are a cause of familial Parkinson's disease (PD). PINK1 protein has been localised to mitochondria and PINK1 gene knockout models ... [more ▼]

BACKGROUND: Mutations of the gene for PTEN-induced kinase 1 (PINK1) are a cause of familial Parkinson's disease (PD). PINK1 protein has been localised to mitochondria and PINK1 gene knockout models exhibit abnormal mitochondrial function. The purpose of this study was to determine whether cells derived from PD patients with a range of PINK1 mutations demonstrate similar defects of mitochondrial function, whether the nature and severity of the abnormalities vary between mutations and correlate with clinical features. METHODOLOGY: We investigated mitochondrial bioenergetics in live fibroblasts from PINK1 mutation patients using single cell techniques. We found that fibroblasts from PINK1 mutation patients had significant defects of bioenergetics including reduced mitochondrial membrane potential, altered redox state, a respiratory deficiency that was determined by substrate availability, and enhanced sensitivity to calcium stimulation and associated mitochondrial permeability pore opening. There was an increase in the basal rate of free radical production in the mutant cells. The pattern and severity of abnormality varied between different mutations, and the less severe defects in these cells were associated with later age of onset of PD. CONCLUSIONS: The results provide insight into the molecular pathology of PINK1 mutations in PD and also confirm the critical role of substrate availability in determining the biochemical phenotype--thereby offering the potential for novel therapeutic strategies to circumvent these abnormalities. [less ▲]

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See detailPINK1-interacting proteins: Proteomic analysis of overexpressed PINK1
Rakovic, Aleksandar; Grünewald, Anne UL; Voges, Lisa et al

in Parkinsons Dis (2011), 2011

Recent publications suggest that the Parkinson's disease- (PD-) related PINK1/Parkin pathway promotes elimination of dysfunctional mitochondria by autophagy. We used tandem affinity purification (TAP ... [more ▼]

Recent publications suggest that the Parkinson's disease- (PD-) related PINK1/Parkin pathway promotes elimination of dysfunctional mitochondria by autophagy. We used tandem affinity purification (TAP), SDS-PAGE, and mass spectrometry as a first step towards identification of possible substrates for PINK1. The cellular abundance of selected identified interactors was investigated by Western blotting. Furthermore, one candidate gene was sequenced in 46 patients with atypical PD. In addition to two known binding partners (HSP90, CDC37), 12 proteins were identified using the TAP assay; four of which are mitochondrially localized (GRP75, HSP60, LRPPRC, and TUFM). Western blot analysis showed no differences in cellular abundance of these proteins comparing PINK1 mutant and control fibroblasts. When sequencing LRPPRC, four exonic synonymous changes and 20 polymorphisms in noncoding regions were detected. Our study provides a list of putative PINK1 binding partners, confirming previously described interactions, but also introducing novel mitochondrial proteins as potential components of the PINK1/Parkin mitophagy pathway. [less ▲]

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See detailAn unusual neurological syndrome of crawling gait, dystonia, pyramidal signs, and limited speech.
Arif, Beenish; Grünewald, Anne UL; Fatima, Amara et al

in Movement disorders : official journal of the Movement Disorder Society (2011), 26(12), 2279-83

BACKGROUND: The purpose of the study was to identify and molecularly characterize a neurological syndrome in a consanguineous Pakistani family. METHODS: Five patients, their 2 siblings, and their parents ... [more ▼]

BACKGROUND: The purpose of the study was to identify and molecularly characterize a neurological syndrome in a consanguineous Pakistani family. METHODS: Five patients, their 2 siblings, and their parents were clinically examined. DNA from all 7 siblings was genotyped with Affymetrix SNP arrays and sequencing of selected candidate genes. RESULTS: An unusual neurological syndrome of crawling gait, predominant leg dystonia, pyramidal signs, microcephaly, and suspected deafness segregated in the family. Three patients ambulated on hands and knees, either by hopping and crossing their legs, or by dragging the legs behind them. Two patients have acquired the ability to walk bipedally with a dystonic gait. Unexpectedly, no chromosomal region was homozygous in patients only. Under different disease models, we localized 7 chromosomal regions in the genome common to all patients. No pathogenic mutations were identified in selected candidate genes or the mitochondrial genome. CONCLUSION: We describe an unusual movement disorder syndrome reminiscent of but distinct from Uner Tan syndrome. [less ▲]

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See detailEffect of endogenous mutant and wild-type PINK1 on Parkin in fibroblasts from Parkinson disease patients.
Rakovic, Aleksandar; Grünewald, Anne UL; Seibler, Philip et al

in Human molecular genetics (2010), 19(16), 3124-37

Mutations in the PTEN-induced putative kinase 1 (PINK1), a mitochondrial serine-threonine kinase, and Parkin, an E3 ubiquitin ligase, are associated with autosomal-recessive forms of Parkinson disease (PD ... [more ▼]

Mutations in the PTEN-induced putative kinase 1 (PINK1), a mitochondrial serine-threonine kinase, and Parkin, an E3 ubiquitin ligase, are associated with autosomal-recessive forms of Parkinson disease (PD). Both are involved in the maintenance of mitochondrial integrity and protection from multiple stressors. Recently, Parkin was demonstrated to be recruited to impaired mitochondria in a PINK1-dependent manner, where it triggers mitophagy. Using primary human dermal fibroblasts originating from PD patients with various PINK1 mutations, we showed at the endogenous level that (i) PINK1 regulates the stress-induced decrease of endogenous Parkin; (ii) mitochondrially localized PINK1 mediates the stress-induced mitochondrial translocation of Parkin; (iii) endogenous PINK1 is stabilized on depolarized mitochondria; and (iv) mitochondrial accumulation of full-length PINK1 is sufficient but not necessary for the stress-induced loss of Parkin signal and its mitochondrial translocation. Furthermore, we showed that different stressors, depolarizing or non-depolarizing, led to the same effect on detectable Parkin levels and its mitochondrial targeting. Although this effect on Parkin was independent of the mitochondrial membrane potential, we demonstrate a differential effect of depolarizing versus non-depolarizing stressors on endogenous levels of PINK1. Our study shows the necessity to introduce an environmental factor, i.e. stress, to visualize the differences in the interaction of PINK1 and Parkin in mutants versus controls. Establishing human fibroblasts as a suitable model for studying this interaction, we extend data from animal and other cellular models and provide experimental evidence for the generally held notion of PD as a condition with a combined genetic and environmental etiology. [less ▲]

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See detailMutant Parkin impairs mitochondrial function and morphology in human fibroblasts.
Grünewald, Anne UL; Voges, Lisa; Rakovic, Aleksandar et al

in PloS one (2010), 5(9), 12962

BACKGROUND: Mutations in Parkin are the most common cause of autosomal recessive Parkinson disease (PD). The mitochondrially localized E3 ubiquitin-protein ligase Parkin has been reported to be involved ... [more ▼]

BACKGROUND: Mutations in Parkin are the most common cause of autosomal recessive Parkinson disease (PD). The mitochondrially localized E3 ubiquitin-protein ligase Parkin has been reported to be involved in respiratory chain function and mitochondrial dynamics. More recent publications also described a link between Parkin and mitophagy. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the impact of Parkin mutations on mitochondrial function and morphology in a human cellular model. Fibroblasts were obtained from three members of an Italian PD family with two mutations in Parkin (homozygous c.1072delT, homozygous delEx7, compound-heterozygous c.1072delT/delEx7), as well as from two relatives without mutations. Furthermore, three unrelated compound-heterozygous patients (delEx3-4/duplEx7-12, delEx4/c.924C>T and delEx1/c.924C>T) and three unrelated age-matched controls were included. Fibroblasts were cultured under basal or paraquat-induced oxidative stress conditions. ATP synthesis rates and cellular levels were detected luminometrically. Activities of complexes I-IV and citrate synthase were measured spectrophotometrically in mitochondrial preparations or cell lysates. The mitochondrial membrane potential was measured with 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide. Oxidative stress levels were investigated with the OxyBlot technique. The mitochondrial network was investigated immunocytochemically and the degree of branching was determined with image processing methods. We observed a decrease in the production and overall concentration of ATP coinciding with increased mitochondrial mass in Parkin-mutant fibroblasts. After an oxidative insult, the membrane potential decreased in patient cells but not in controls. We further determined higher levels of oxidized proteins in the mutants both under basal and stress conditions. The degree of mitochondrial network branching was comparable in mutants and controls under basal conditions and decreased to a similar extent under paraquat-induced stress. CONCLUSIONS: Our results indicate that Parkin mutations cause abnormal mitochondrial function and morphology in non-neuronal human cells. [less ▲]

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See detailDifferential effects of PINK1 nonsense and missense mutations on mitochondrial function and morphology.
Grünewald, Anne UL; Gegg, M. E.; Taanman, J.-W. et al

in Experimental neurology (2009), 219(1), 266-73

Mutations of the PINK1 gene are a cause of autosomal recessive Parkinson's disease (PD). PINK1 encodes a mitochondrial kinase of unknown function which is widely expressed in both neuronal and non ... [more ▼]

Mutations of the PINK1 gene are a cause of autosomal recessive Parkinson's disease (PD). PINK1 encodes a mitochondrial kinase of unknown function which is widely expressed in both neuronal and non-neuronal cells. We have studied fibroblast cultures from four family members harbouring the homozygous p.Q456X mutation in PINK1, three of their wild-type relatives, one individual with the homozygous p.V170G mutation and five independent controls. Results showed bioenergetic abnormalities involving decreased activities of complexes I and IV along with increased activities of complexes II and III in the missense p.V170G mutant. There were increased basal levels of mitochondrial superoxide dismutase in these cells and an exaggerated increase of reduced glutathione in response to paraquat-induced free radical formation. Furthermore, swollen and enlarged mitochondria were observed in this sample. In the p.Q456X nonsense mutants, the respiratory chain enzymes were unaffected, but ATP levels were significantly decreased. These results confirm that mutations of PINK1 cause abnormal mitochondrial morphology, bioenergetic function and oxidative metabolism in human tissues but suggest that the biochemical consequences may vary between mutations. [less ▲]

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See detailRe: Alpha-synuclein gene duplication is present in sporadic Parkinson disease.
Brueggemann, N.; Odin, P.; Grünewald, Anne UL et al

in Neurology (2008), 71(16), 12941294

Detailed reference viewed: 53 (7 UL)
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See detailThe DRD2 TaqIA polymorphism and demand of dopaminergic medication in Parkinson's disease.
Paus, Sebastian; Grünewald, Anne UL; Klein, Christine UL et al

in Movement disorders : official journal of the Movement Disorder Society (2008), 23(4), 599-602

Previous studies have demonstrated that the TaqIA polymorphism of the D2 dopamine receptor gene (DRD2) is associated with response to dopaminergic and antidopaminergic treatment in Parkinson's disease (PD ... [more ▼]

Previous studies have demonstrated that the TaqIA polymorphism of the D2 dopamine receptor gene (DRD2) is associated with response to dopaminergic and antidopaminergic treatment in Parkinson's disease (PD) and schizophrenia, respectively. We tested whether the TaqIA genotype in PD is responsible for demand of dopaminergic medication, measured in total dopaminergic load per year of disease, in a large scale association study based on the gene bank of the German Competence Network on Parkinson's disease. Regression analysis yielded no significant differences between the TaqIA genotypes. We conclude that the DRD2 TaqIA polymorphism alone has no pivotal role for interindividual variability of dopaminergic requirement in PD. We propose a practicable system of measuring dopaminergic treatment for future pharmacogenetic studies in PD. [less ▲]

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See detailMyoclonus-dystonia: significance of large SGCE deletions.
Grünewald, Anne UL; Djarmati, A.; Lohmann-Hedrich, K. et al

in Human mutation (2008), 29(2), 331-2

Myoclonus-dystonia (M-D) is an autosomal-dominant movement disorder caused by mutations in SGCE. We investigated the frequency and type of SGCE mutations with emphasis on gene dosage alterations and ... [more ▼]

Myoclonus-dystonia (M-D) is an autosomal-dominant movement disorder caused by mutations in SGCE. We investigated the frequency and type of SGCE mutations with emphasis on gene dosage alterations and explored the associated phenotypes. We tested 35 M-D index patients by multiplex ligation-dependent probe amplification (MLPA) and genomic sequencing. Mutations were found in 26% (9/35) of the cases, all but three with definite M-D. Two heterozygous deletions of the entire SGCE gene and flanking DNA and a heterozygous deletion of exon 2 only were detected, accounting for 33% (3/9) of the mutations found. Both large deletions contained COL1A2 and were additionally associated with joint problems. Further, we discovered one novel small deletion (c.771_772delAT, p.C258X) and four recurrent point mutations (c.289C>T, p.R97X; c.304C>T, p.R102X; c.709C>T, p.R237X; c.1114C>T, p.R372X). A Medline search identified 22 articles on SGCE mutational screening. Sixty-four unrelated M-D patients were described with 41 different mutations. No genotype-phenotype association was found, except in patients with deletions encompassing additional genes. In conclusion, a rigorous clinical preselection of patients and careful accounting for non-motor signs should precede mutational tests. Gene dosage studies should be included in routine SGCE genetic testing. [less ▲]

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See detailAutosomal dominant myoclonus-dystonia and Tourette syndrome in a family without linkage to the SGCE gene.
Orth, Michael; Djarmati, Ana; Baumer, Tobias et al

in Movement disorders : official journal of the Movement Disorder Society (2007), 22(14), 2090-6

The objective of this study was to report clinical details and results of genetic testing for mutations in the epsilon-sarcoglycan (SGCE) gene, the Slit and Trk-like 1 (SLITRK1) gene and for linkage to ... [more ▼]

The objective of this study was to report clinical details and results of genetic testing for mutations in the epsilon-sarcoglycan (SGCE) gene, the Slit and Trk-like 1 (SLITRK1) gene and for linkage to the DYT15, DYT1, and DRD2 gene loci in a family with autosomal dominant myoclonus-dystonia (M-D) and Gilles de la Tourette syndrome (GTS). Fourteen family members, from three generations, underwent a detailed clinical assessment and donated DNA samples. The SGCE and the SLITRK1 gene were sequenced and investigated by gene dosage analysis in selected family members. Linkage to the SGCE, DYT15, DYT1, DRD2, and SLITRK1 loci was also tested. RESULTS: We included three healthy and 11 affected family members with M-D (n = 3), dystonia alone (n = 2), GTS (n = 1), tics (n = 1) or a combination of these with obsessive compulsive disorder (OCD) (M-D + OCD: n = 2; dystonia+OCD: n = 1; M-D + GTS + OCD: n = 1). There was no linkage to the SGCE, DYT15, DYT1 or DRD2 loci. No changes were found in the SLITRK1 gene. The presence of both M-D and GTS in one family, in which all known M-D loci and a recently discovered GTS locus were excluded, suggests a novel susceptibility gene for both M-D and GTS. [less ▲]

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See detailRapid and reliable detection of exon rearrangements in various movement disorders genes by multiplex ligation-dependent probe amplification.
Djarmati, Ana; Guzvic, Miodrag; Grünewald, Anne UL et al

in Movement disorders : official journal of the Movement Disorder Society (2007), 22(12), 1708-14

Because of the occurrence of different types of mutations, comprehensive genetic testing for Parkinson's disease (PD), dopa-responsive dystonia (DRD), and myoclonus-dystonia (M-D) should include screening ... [more ▼]

Because of the occurrence of different types of mutations, comprehensive genetic testing for Parkinson's disease (PD), dopa-responsive dystonia (DRD), and myoclonus-dystonia (M-D) should include screening for small sequence changes and for large exonic rearrangements in disease-associated genes. In diagnostic and research settings, the latter is frequently omitted or performed by laborious and expensive quantitative real-time PCR (qPCR). Our study aimed to evaluate the utility of a novel method, multiplex ligation-dependent probe amplification (MLPA), in molecular diagnostics of movement disorders. We have analyzed, by MLPA, genomic DNA from 21 patients affected with PD, DRD, or M-D, in which the presence of exon rearrangement(s) (n = 20) or of a specific point mutation (detectable by MLPA, n = 1) had been established previously by qPCR or sequencing. In parallel, we have studied, in a blinded fashion, DNA from 49 patients with an unknown mutational status. Exon rearrangements were evident in 20 samples with previously established mutations; in the 21st sample the known specific point mutation was detected. We conclude that MLPA represents a reliable method for large-scale and cost-effective gene dosage screening of various movement disorders genes. This finding reaches far beyond a simple technical advancement and has two major implications: (1) By improving the availability of comprehensive genetic testing, it supports clinicians in the establishment of a genetically defined diagnosis; (2) By enabling gene dosage testing of several genes simultaneously, it significantly facilitates the mutational analysis of large patient and control populations and thereby constitutes the prerequisite for meaningful phenotype-genotype correlations. [less ▲]

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See detailBiological effects of the PINK1 c.1366C>T mutation: implications in Parkinson disease pathogenesis.
Grünewald, Anne UL; Breedveld, Guido J.; Lohmann-Hedrich, Katja et al

in Neurogenetics (2007), 8(2), 103-9

PINK1 gene mutations are a cause of recessively inherited, early-onset Parkinson's disease. In some patients, a single heterozygous mutation has been identified, including the recurrent c.1366C>T ... [more ▼]

PINK1 gene mutations are a cause of recessively inherited, early-onset Parkinson's disease. In some patients, a single heterozygous mutation has been identified, including the recurrent c.1366C>T transition. The interpretation of this finding remains controversial. Furthermore, the c.1366C>T mutation is associated with lower levels of PINK1 transcript, raising the question of whether mRNA levels correlate with the clinical status. We sequenced genomic DNA and copy DNA (cDNA) from 20 subjects carrying the c.1366C>T mutation in the homozygous (n = 5) or heterozygous (n = 15) state. In 17 mutation carriers, messenger RNA (mRNA) was quantified by real-time PCR using four different assays (PINK1 exon 5-6 or exon 7-8 relative to control genes SDHA or YWHAZ). Genomic sequencing confirmed the presence and zygosity of PINK1 mutations. cDNA sequencing in heterozygous mutation carriers revealed a strong wild-type and a much weaker or almost absent mutant signal, whereas in the homozygous patients, only the mutant signal was detected. Homozygous and heterozygous carriers showed PINK1 mRNA levels relative to a reference gene in the range of 0.1-0.2 and 0.5-0.6, respectively, compared with values of 0.9-1.0 in mutation-negative individuals. Treatment of lymphoblasts from a heterozygous mutation carrier with cycloheximide markedly increased the mutant transcript signal. We conclude that the recurrent PINK1 c.1366C>T mutation exerts a major effect at the mRNA level (80-90% reduction), most likely via nonsense-mediated mRNA decay. The absence of correlation between PINK1 mRNA levels and clinical status in heterozygous mutation carriers suggests that other genetic or environmental factors play a role in determining the phenotypic variability associated with the c.1366C>T mutation. [less ▲]

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See detailEarly-onset parkinsonism associated with PINK1 mutations: frequency, genotypes, and phenotypes.
Klein, Christine UL; Grünewald, Anne UL; Hedrich, Katja

in Neurology (2006), 66(7), 1129-301129-30

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See detailClinical spectrum of homozygous and heterozygous PINK1 mutations in a large German family with Parkinson disease: role of a single hit?
Hedrich, Katja; Hagenah, Johann; Djarmati, Ana et al

in Archives of neurology (2006), 63(6), 833-8

BACKGROUND: Although homozygous mutations in the PTEN-induced putative kinase 1 (PINK1) gene have been unequivocally associated with early-onset Parkinson disease (PD), the role of single heterozygous ... [more ▼]

BACKGROUND: Although homozygous mutations in the PTEN-induced putative kinase 1 (PINK1) gene have been unequivocally associated with early-onset Parkinson disease (PD), the role of single heterozygous PINK1 mutations is less clear. OBJECTIVE: To investigate the role of homozygous and heterozygous PINK1 mutations in a large German pedigree (family W). DESIGN: Mutation analysis of PINK1 and results of standardized neurological and motor examination by 3 independent movement disorder specialists, including blinded video rating. SETTINGS: University of Lubeck. PARTICIPANTS: Twenty family members. MAIN OUTCOME MEASURES: The PINK1 genotype and PD status of all family members. RESULTS: The index patient of family W carried a homozygous nonsense mutation (c.1366C>T; p.Q456X) and presented with a phenotype closely resembling idiopathic PD but with an onset at 39 years of age. The family included a total of 4 affected homozygous members (age, 60-71 years; age at onset, 39-61 years), 6 members with slight or mild signs of PD (affected) and a heterozygous mutation (age, 31-49 years), and 5 unaffected heterozygous mutation carriers (age, 34-44 years). Although none of the heterozygous affected family members was aware of their signs (asymptomatic), the clinical findings were unequivocal and predominantly or exclusively present on their dominant right-hand side, eg, unilaterally reduced or absent arm swing and unilateral rigidity. The heterozygous members were all considerably younger than the affected homozygous mutation carriers. CONCLUSIONS: Heterozygous PINK1 mutations may predispose to PD, as was previously suggested by the presence of dopamine hypometabolism in asymptomatic mutation carriers. Long-term follow-up of our large family W provides an excellent opportunity to further evaluate the role of single heterozygous PINK1 mutations later in life, which will have major implications on genetic counseling. [less ▲]

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