The parkin gene and its phenotype. Italian PD Genetics Study Group, French PD Genetics Study Group and the European Consortium on Genetic Susceptibility in Parkinson's Disease.
ABSTRACT Mutations of the parkin gene on chromosome 6 cause autosomal recessive, early onset parkinsonism. This is the most frequent form of monogenic parkinsonism so far identified. The associated phenotypical spectrum encompasses early onset, levodopa-responsive parkinsonism (average onset in the early 30s in Europe), and it overlaps with dopa-responsive dystonia in cases with the earliest onset, and with clinically typical Parkinson's disease in cases with later onset. Despite clinical features, Lewy bodies are not found at autopsy in brains of patients with parkin mutations. The parkin protein possesses ubiquitin ligase activity, which is abolished by the pathogenic mutations.
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ABSTRACT: DYT-5 dystonia usually presents as a dopa-responsive dystonia (DRD) with early or late parkinsonian manifestations and/or dystonic features. Genetically, these patients have been described as having a wide array of independent mutations in the guanosine triphosphate cyclohydrolase 1 gene (GCH1), and these patients may also have a wide array of clinical manifestations. A Colombian family with six affected female members was characterized. Three members, including the index case, revealed mild parkinsonism, whereas three granddaughters of the index case showed severe generalized dystonia. No men were affected. There was anticipation, and a female predominance was uncovered. Treatment with levodopa was generally effective except in a case with severe skeletal deformities and contractions. Detailed genetic analysis in the index case revealed a new mutation in exon 1 of GCH1 (c.159delG). This study revealed a new mutation of GCH1 that resulted in heterogeneous clinical presentations of DRD within a large family.Tremor and other hyperkinetic movements (New York, N.Y.). 01/2013; 3.
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ABSTRACT: The identification of rare monogenic forms of Parkinson's disease (PD) has provided tremendous insight into the molecular pathogenesis of this disorder. Heritable mutations in a-synuclein, parkin, DJ-1 and PINK1 cause familial forms of PD. In the more common sporadic form of PD, oxidative stress and derangements in mitochondrial complex-I function are considered to play a prominent role in disease pathogenesis. However, the relationship of DJ-1 with other PD-linked genes and oxidative stress has not been explored. Here, we show that pathogenic mutant forms of DJ-1 specifically but differentially associate with parkin, an E3 ubiquitin ligase. Chemical cross-linking shows that pathogenic DJ-1 mutants exhibit impair- ments in homo-dimer formation, suggesting that parkin may bind to monomeric DJ-1. Parkin fails to specifi- cally ubiquitinate and enhance the degradation of L166P and M26I mutant DJ-1, but instead promotes their stability in cultured cells. The interaction of parkin with L166P DJ-1 may involve a larger protein complex that contains CHIP and Hsp70, perhaps accounting for the lack of parkin-mediated ubiquitination. Oxidative stress also promotes an interaction between DJ-1 and parkin, but this does not result in the ubiqui- tination or degradation of DJ-1. Parkin-mediated alterations in DJ-1 protein stability may be pathogenically relevant as DJ-1 levels are dramatically increased in the detergent-insoluble fraction from sporadic PD/ DLB brains, but are reduced in the insoluble fraction from parkin-linked autosomal recessive juvenile-onset PD brains. These data potentially link DJ-1 and parkin in a common molecular pathway at multiple levels that may have important implications for understanding the pathogenesis of inherited and sporadic PD.Human Molecular Genetics 02/2005; 14(1). · 7.69 Impact Factor
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ABSTRACT: Although Parkinson's disease (PD) was first described almost 200 years ago, it remains an incurable disease with a cause that is not fully understood. Nowadays it is known that disturbances in the structure of pathological proteins in PD can be caused by more than environmental and genetic factors. Despite numerous debates and controversies in the literature about the role of mutations in the SNCA and PRKN genes in the pathogenesis of PD, it is evident that these genes play a key role in maintaining dopamine (DA) neuronal homeostasis and that the dysfunction of this homeostasis is relevant to both familial (FPD) and sporadic (SPD) PD with different onset. In recent years, the importance of alphasynuclein (ASN) in the process of neurodegeneration and neuroprotective function of the Parkin is becoming better understood. Moreover, there have been an increasing number of recent reports indicating the importance of the interaction between these proteins and their encoding genes. Among others interactions, it is suggested that even heterozygous substitution in the PRKN gene in the presence of the variants +2/+2 or +2/+3 of NACP-Rep1 in the SNCA promoter, may increase the risk of PD manifestation, which is probably due to ineffective elimination of over-expressed ASN by the mutated Parkin protein. Finally, it seems that genetic testing may be an important part of diagnostics in patients with PD and may improve the prognostic process in the course of PD. However, only full knowledge of the mechanism of the interaction between the genes associated with the pathogenesis of PD is likely to help explain the currently unknown pathways of selective damage to dopaminergic neurons in the course of PD.Current Genomics 12/2013; 14(8):502-17. · 2.48 Impact Factor