References of "Bauer, Peter"
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See detailEIF4G1 is neither a strong nor a common risk factor for Parkinson's disease: evidence from large European cohorts
Huttenlocher, Johanna; Krüger, Rejko UL; Capetian, Philipp et al

in Journal of medical genetics (2014), 0

BACKGROUND: Missense mutations in the eukaryotic translation initiation factor 4-gamma 1 (EIF4G1) gene have previously been implicated in familial Parkinson's disease (PD). A large PD family with ... [more ▼]

BACKGROUND: Missense mutations in the eukaryotic translation initiation factor 4-gamma 1 (EIF4G1) gene have previously been implicated in familial Parkinson's disease (PD). A large PD family with autosomal-dominant segregation showed a heterozygous missense mutation and additional patients were found to have unique sequence variants that have not been observed in controls. Subsequent studies have reported contradictory findings. METHODS: We assessed the relevance of EIF4G1 mutations in a European cohort of 2146 PD patients. Of these, 2051 sporadic PD patients were screened for the reported p.Ala502Val and p.Arg1205His mutations. In addition, the complete coding region of EIF4G1 was directly sequenced in 95 familial PD patients with autosomal-dominant inheritance. Moreover, we imputed the p.Arg1205His substitution and tested for association with PD in the Icelandic population (93 698 samples). RESULTS: We did not observe the presence of the p.Ala502Val substitution in our cohort; however, the p.Arg1205His mutation was identified in one sporadic PD patient. The same mutation was also found in 76 Icelandic subjects older than 65 years using haplotype imputing. Only five of these subjects reported PD symptoms (OR 1.3, p=0.50). Thus, if causal, the p.Arg1205His EIF4G1 mutation has a low penetrance or a late onset manifestation. A novel variant p.Arg566Cys found in a patient with familial PD did not cosegregate with PD in all three affected siblings. All further recently published EIF4G1 mutations found in our cohort are likely to be benign polymorphisms. CONCLUSIONS: This is the largest genetic study of EIF4G1 mutations in PD. Our data do not support the EIF4G1 gene as a high-risk PD locus, neither for the familial nor the sporadic condition. Furthermore, the p.Arg1205His mutation is not significantly associated with increased risk of PD in the Icelandic population. Therefore, caution should be exercised when interpreting EIF4G1 genotyping results in isolated patients and PD families. In summary, diagnostic testing of EIF4G1 should not be recommended in clinical settings. [less ▲]

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See detailDe novo mutations in hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS).
Karle, Kathrin N.; Biskup, Saskia; Schule, Rebecca et al

in Neurology (2013), 81(23), 2039-44

OBJECTIVE: Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is caused by autosomal-dominantly inherited mutations in the colony stimulating factor 1 receptor (CSF1R) gene, and is ... [more ▼]

OBJECTIVE: Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is caused by autosomal-dominantly inherited mutations in the colony stimulating factor 1 receptor (CSF1R) gene, and is clinically characterized by a progressive cognitive and motor decline leading to death within several years. METHODS: In a continuous series of 25 patients with adult-onset leukoencephalopathy of unknown cause, we genetically confirmed HDLS in 6 families. Affected and nonaffected individuals were examined clinically and by brain MRI studies. RESULTS: HDLS presented as prominent dementia and apraxia, often with extrapyramidal and pyramidal signs, rarely with ataxia. White matter MRI changes were detectable early in the disease course. Family history was negative in 4 of 6 index patients. In 2 of 6 index patients, we could confirm the occurrence of de novo mutations in the CSF1R gene. One family showed possible incomplete penetrance: the 69-year-old father of the index patient carried a CSF1R mutation but was clinically unaffected. In one family, the parents were apparently unaffected and not available for genetic testing. CONCLUSIONS: Typical clinical phenotype and early brain MRI alterations can help to guide the diagnosis of HDLS. Because we confirmed de novo mutations in one-third of patients with CSF1R mutations, this diagnosis should be considered even in the absence of a family history. Furthermore, we present evidence for reduced penetrance of a CSF1R mutation. These results have substantial impact for genetic counseling of asymptomatic individuals at risk and should foster research into disease-modifying factors. [less ▲]

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See detailThe modulation of Amyotrophic Lateral Sclerosis risk by ataxin-2 intermediate polyglutamine expansions is a specific effect.
Gispert, Suzana; Kurz, Alexander; Waibel, Stefan et al

in Neurobiology of disease (2012), 45(1), 356-61

Full expansions of the polyglutamine domain (polyQ>/=34) within the polysome-associated protein ataxin-2 (ATXN2) are the cause of a multi-system neurodegenerative disorder, which usually presents as a ... [more ▼]

Full expansions of the polyglutamine domain (polyQ>/=34) within the polysome-associated protein ataxin-2 (ATXN2) are the cause of a multi-system neurodegenerative disorder, which usually presents as a Spino-Cerebellar Ataxia and is therefore known as SCA2, but may rarely manifest as Levodopa-responsive Parkinson syndrome or as motor neuron disease. Intermediate expansions (27</=polyQ</=33) were reported to modify the risk of Amyotrophic Lateral Sclerosis (ALS). We have now tested the reproducibility and the specificity of this observation. In 559 independent ALS patients from Central Europe, the association of ATXN2 expansions (30</=polyQ</=35) with ALS was highly significant. The study of 1490 patients with Parkinson's disease (PD) showed an enrichment of ATXN2 alleles 27/28 in a subgroup with familial cases, but the overall risk of sporadic PD was unchanged. No association was found between polyQ expansions in Ataxin-3 (ATXN3) and ALS risk. These data indicate a specific interaction between ATXN2 expansions and the causes of ALS, possibly through altered RNA-processing as a common pathogenic factor. [less ▲]

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See detailDissecting the role of the mitochondrial chaperone mortalin in Parkinson's disease: functional impact of disease-related variants on mitochondrial homeostasis.
Burbulla, Lena F.; Schelling, Carina; Kato, Hiroki et al

in Human molecular genetics (2010), 19(22), 4437-52

The mitochondrial chaperone mortalin has been linked to neurodegeneration in Parkinson's disease (PD) based on reduced protein levels in affected brain regions of PD patients and its interaction with the ... [more ▼]

The mitochondrial chaperone mortalin has been linked to neurodegeneration in Parkinson's disease (PD) based on reduced protein levels in affected brain regions of PD patients and its interaction with the PD-associated protein DJ-1. Recently, two amino acid exchanges in the ATPase domain (R126W) and the substrate-binding domain (P509S) of mortalin were identified in Spanish PD patients. Here, we identified a separate and novel variant (A476T) in the substrate-binding domain of mortalin in German PD patients. To define a potential role as a susceptibility factor in PD, we characterized the functions of all three variants in different cellular models. In vitro import assays revealed normal targeting of all mortalin variants. In neuronal and non-neuronal human cell lines, the disease-associated variants caused a mitochondrial phenotype of increased reactive oxygen species and reduced mitochondrial membrane potential, which were exacerbated upon proteolytic stress. These functional impairments correspond with characteristic alterations of the mitochondrial network in cells overexpressing mutant mortalin compared with wild-type (wt), which were confirmed in fibroblasts from a carrier of the A476T variant. In line with a loss of function hypothesis, knockdown of mortalin in human cells caused impaired mitochondrial function that was rescued by wt mortalin, but not by the variants. Our genetic and functional studies of novel disease-associated variants in the mortalin gene define a loss of mortalin function, which causes impaired mitochondrial function and dynamics. Our results support the role of this mitochondrial chaperone in neurodegeneration and underscore the concept of impaired mitochondrial protein quality control in PD. [less ▲]

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See detailA comprehensive genetic study of the proteasomal subunit S6 ATPase in German Parkinson's disease patients.
Wahl, Claudia; Kautzmann, Sabine; Krebiehl, Guido et al

in Journal of neural transmission (Vienna, Austria : 1996) (2008), 115(8), 1141-8

Dysfunction of proteasomal protein degradation is involved in neurodegeneration in Parkinson's disease (PD). Recently we identified the regulatory proteasomal subunit S6 ATPase as a novel interactor of ... [more ▼]

Dysfunction of proteasomal protein degradation is involved in neurodegeneration in Parkinson's disease (PD). Recently we identified the regulatory proteasomal subunit S6 ATPase as a novel interactor of synphilin-1, which is a substrate of the ubiquitin-ligase Parkin (PARK2) and an interacting protein of alpha-synuclein (PARK1). To further investigate a potential role in the pathogenesis of PD, we performed a detailed mutation analysis of the S6 ATPase gene in a large sample of 486 German sporadic and familial PD patients. Direct sequencing revealed two novel intronic variants. An insertion/deletion variant in intron 5 of the S6 ATPase gene was more frequent in patients compared to controls. Moreover, this variant was significantly more frequent in early-onset compared to late-onset PD patients. The identification of a genetic link between a regulatory proteasomal subunit and PD further underscores the relevance of disturbed protein degradation in PD. [less ▲]

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See detailMitochondrial translation initiation factor 3 gene polymorphism associated with Parkinson's disease.
Abahuni, Nadine; Gispert, Suzana; Bauer, Peter et al

in Neuroscience letters (2007), 414(2), 126-9

Mitochondrial dysfunction occurs early in late-onset sporadic Parkinson's disease (PD), but the mitochondrial protein network mediating PD pathogenesis is largely unknown. Mutations in the mitochondrial ... [more ▼]

Mitochondrial dysfunction occurs early in late-onset sporadic Parkinson's disease (PD), but the mitochondrial protein network mediating PD pathogenesis is largely unknown. Mutations in the mitochondrial serine-threonine kinase PINK1 have recently been shown to cause the early-onset autosomal recessive PARK6 variant of PD. We have now tested a candidate interactor protein of PINK1, the mitochondrial translation initiation factor 3 (MTIF3) for involvement in PD pathogenesis. In two independent case-control collectives, the c.798C>T polymorphism of the MTIF3 gene showed allelic association with PD, with a maximal significance of p=0.0073. An altered function of variant MTIF3 may affect the availability of mitochondrial encoded proteins, lead to oxidative stress and create vulnerability for PD. [less ▲]

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See detailTranscranial ultrasound in different monogenetic subtypes of Parkinson's disease.
Schweitzer, Katherine J.; Brussel, Theresa; Leitner, Petra et al

in Journal of neurology (2007), 254(5), 613-6

Hyperechogenicity of the substantia nigra (SN) has been found to be a typical sign in idiopathic Parkinson's disease (PD), prevalent in more than 90% of affected individuals. To see whether SN ... [more ▼]

Hyperechogenicity of the substantia nigra (SN) has been found to be a typical sign in idiopathic Parkinson's disease (PD), prevalent in more than 90% of affected individuals. To see whether SN hyperechogenicity is also characteristic for monogenetically caused PD, we investigated PD patients with alpha-synuclein, LRRK2, parkin, PINK1 and DJ-1 mutations by transcranial sonography (TCS). In all these patients the area of SN echogenicity was significantly larger than in healthy controls, but smaller, than in idiopathic PD. As SN hyperechogenicity could be related to an increased iron content of the SN, these findings suggest that iron may play a less significant role in the pathogenesis of monogenetically caused compared to idiopathic PD. [less ▲]

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See detailNovel homozygous p.E64D mutation in DJ1 in early onset Parkinson disease (PARK7).
Hering, Robert; Strauss, Karsten M.; Tao, Xiao et al

in Human mutation (2004), 24(4), 321-9

Mutations in the parkin gene have been identified as a common cause of autosomal recessive inherited Parkinson disease (PD) associated with early disease manifestation. However, based on linkage data ... [more ▼]

Mutations in the parkin gene have been identified as a common cause of autosomal recessive inherited Parkinson disease (PD) associated with early disease manifestation. However, based on linkage data, mutations in other genes contribute to the genetic heterogeneity of early-onset PD (EOPD). Recently, two mutations in the DJ1 gene were described as a second cause of autosomal recessive EOPD (PARK7). Analyzing the PARK7/DJ1 gene in 104 EOPD patients, we identified a third mutation, c.192G>C (p.E64D), associated with EOPD in a patient of Turkish ancestry and characterized the functional significance of this amino acid substitution. In the patient, a substantial reduction of dopamine uptake transporter (DAT) binding was found in the striatum using [(18)F]FP-CIT and PET, indicating a serious loss of presynaptic dopaminergic afferents. His sister, homozygous for E64D, was clinically unaffected but showed reduced dopamine uptake when compared with a clinically unaffected brother, who is heterozygous for E64D. We demonstrate by crystallography that the E64D mutation does not alter the structure of the DJ1 protein, however we observe a tendency towards decreased levels of the mutant protein when overexpressed in HEK293 or COS7 cells. Using immunocytochemistry in contrast to the homogenous nuclear and cytoplasmic staining in HEK293 cells overexpressing wild-type DJ1, about 5% of the cells expressing E64D and up to 80% of the cells expressing the recently described L166P mutation displayed a predominant nuclear localization of the mutant DJ1 protein. [less ▲]

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