Recent studies have shown that the past medical history of Parkinson’s disease more than 1 year before the index-date of colon cancer was associated with lower risks of acquiring colon cancer, suggesting an inverse correlation between the incidence of Parkinson’s disease and of colon cancer [21] ATP13A2 mutation leads to α-synuclein accumulation, which is associated with gut microbiota formation and a higher risk of Parkinson’s disease [6, 22, 23]. The gene discussed is ATP13A2; the disease is Parkinson disease.