Although combining CSF Aβ biomarkers with amyloid neuroimaging biomarkers (e. g., PiB amyloid positron emission tomography) and other CSF biomarkers (e. g., total tau (t-tau) and phosphorylated tau (p-tau)) has proven to be useful for AD diagnosis, other molecular biomarkers are needed to enhance the sensitivity and specificity of diagnosis of various neurodegenerative disorders as well as to differentiate clinical phenotypes of AD. The gene discussed is MAPT; the disease is Alzheimer disease.