[The value of genetic and neuroimaging studies in the differential diagnosis of Parkinson's disease].
BACKGROUND
Parkinson's disease (PD) is usually diagnosed on the basis of clinical criteria. Today there are genetic and neuroimaging tests that can make a valuable contribution to the study of this disease.


OBJECTIVE
To review the recent advances in genetic studies and in neuroimaging techniques applied to PD, as well as looking at their shortcomings, and to analyse the reasons for conducting such tests and to discuss their importance in everyday clinical practice, including a series of reflections on ethical issues.


METHODS
The list of genetic disorders associated with PD is continually being extended and reviewed, and pathological alterations have been defined in at least 10 genes. The most frequent mutations in our setting are to be found in the parkin gene (PARK2) and in the LRKK2 gene (PARK8). These mutations have a penetrance that is not very high and their clinical expression is variable. Images obtained by nuclear resonance, single-photon emission tomography, positron emission tomography or by cranial sonography provide data that can help in the diagnosis of PD and to differentiate it from other diseases. None of the techniques is wholly specific, however, and there are clinico-radiological disagreements.


CONCLUSIONS
The detection of mutations does not allow a clear prognostic differentiation or a distinct therapeutic attitude to be established. The value of neuroimaging techniques in very early phases and in dubious cases is still not altogether clear. Whether establishing a diagnosis in very early phases currently offers the patient any benefits is subject to debate. It would be advisable to attempt to distinguish between tests that are carried out for clinical reasons and those which are conducted for research purposes so as to be able to proceed in the most suitable manner.
Rojo
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A
Hospital Universitario Principe de Asturias, Alcala de Henares, Madrid, Espana. anarojosebastian@gmail.com
Corbella
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C
D003937:Diagnosis, Differential; D003952:Diagnostic Imaging / Q000379:methods*; D004992:Ethics, Medical; D006801:Humans; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D008279:Magnetic Resonance Imaging; D009154:Mutation; D010300:Parkinson Disease / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; C495280:LRRK2 protein, human; D000071158:Leucine-Rich Repeat Serine-Threonine Protein Kinase-2; D017346:Protein Serine-Threonine Kinases