PITX3 and Parkinson disease: Additionally, an allele of rs4919621 SNP (chr10:103988621) in the intron of the Pitx3 gene and the C allele of rs2281983 SNP appeared significantly more often in PD patients with an early age of onset than they did in PD patients who experienced late onset (p = 0.001) and the controls (p = 0.002) [111].