Consequently, NAADP/TPC2/Ca2+ signaling has been shown to play a critical role in a variety of associated pathophysiological processes, including the life cycle of Ebola virus, human immunodeficiency virus (HIV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Parkinson’s disease, Alzheimer’s disease, non-alcoholic fatty liver disease, and cardiac dysfunction [28, 31, 35–42], thus highlighting the importance of the endolysosomal system in a variety of pathophysiological processes. The gene discussed is TPCN2; the disease is Parkinson disease.