Dopaminergic dysfunction in unrelated, asymptomatic carriers of a single parkin mutation.
ABSTRACT Parkin disease is usually autosomal recessive; however, two studies have shown that asymptomatic heterozygotes have nigrostriatal dysfunction and even manifest subtle extrapyramidal signs. The authors used 18F-dopa PET to study 13 asymptomatic parkin heterozygotes and found a significant reduction of (18)F-dopa uptake in caudate, putamen, ventral, and dorsal midbrain compared with control subjects. Four had subtle extrapyramidal signs. Parkin heterozygosity is a risk factor for nigrostriatal dysfunction and in some may contribute to late-onset Parkinson disease.
Movement Disorders 01/2014; 29(1). DOI:10.1002/mds.25759 · 5.63 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. DOI:10.2174/1389202914666131210205839 · 2.87 Impact Factor