SNCA and Parkinson disease: Among many other genes with low penetrance relative to previously identified causative, higher-penetrance PD genes such as SNCA, PARK2, and LRRK2, this GWAS study also identified as PD risk factors NFKB2, encoding a subunit of the Nf-κB complex, SCAF11, encoding a caspase, and KCNS3 and KCNIP3, both encoding voltage-gated potassium channel subunits (Kv9.3 and calsenilin).