It turned out that the patient carried a point mutation of valine to isoleucine at codon 180, as well as an MM polymorphism at codon 129 in PRNP. No mutations were detected in FTD-related genes, such as MAPT, GRN, TARDBP, FUS, C9orf72, VCP, CHMP2B, SQSTM1, and TBK1. The gene discussed is C9orf72; the disease is frontotemporal dementia.