Genetic heterogeneity in Parkinson disease: The meaning of GWAS and replication studies
Parkinson disease (PD) is considered a sporadic neurodegenerative disorder, though genetic factors are frequently involved in its etiology. That some familial presentations of PD have been associated with different mutated genes suggests that some genetic variants can also modulate the risk for "nonfamilial" presentation of PD. The hypothesis-free genome-wide association studies (GWAS) performed in PD and healthy controls(1,2) revealed that certain allele variants can increase the risk of sporadic PD. Replication studies are important, since they allow investigation of whether the risk loci found in the GWAS are also associated with PD in other populations, thus excluding spurious associations that could be a result, for instance, of an undetected population structure or from genotyping errors.
CITATION Neurology. 2012 Jul 11