Rapid advances in human genomics are revealing the full spectrum of genetic susceptibility factors for Parkinson disease (PD). Among the insights are the remarkable number and variety of identified genomic variations, including rare point mutations, common single-nucleotide polymorphisms, and copy number changes. In fact, multiple classes of alleles affecting the same gene have been independently linked to PD risk, such as at the α-synuclein locus.1 Now, Butcher et al2 report clinical and pathological studies implicating 22q11.2 deletion syndrome (22q11.2DS) as a novel putative PD risk factor. If confirmed, this would be among the first discoveries that genomic microdeletions can contribute to PD susceptibility, highlighting the role of structural variation among the enlarging collection of risk alleles.
Shulman JM. Structural Variation and the Expanding Genomic Architecture of Parkinson Disease. JAMA Neurol. 2013;70(11):1355-1356. doi:10.1001/jamaneurol.2013.4263