A study conducted by Noguchi et al. showed that tau protein levels in serum are markedly higher in the CJD group (193 ± 72.6 pg/mL) compared to AD (0 ± 3.3 pg/mL), non-CJD with rapidly progressive dementia (22 ± 21.8 pg/mL), and the healthy control group (0 ± 9.37 pg/mL). The gene discussed is MAPT; the disease is Alzheimer disease.