Schizophrenia, bipolar disorders (SEPT5, 6, and 11) (Pennington et al. 2008), Down syndrome (SEPT4, 6, and 7) (Sitz et al. 2008), Alzheimer’s disease (SEPT1, 2, and 4) (Kinoshita et al. 1998), and Parkinson’s disease (SEPT4) (Ihara et al. 2007) were all associated to abnormalities of septin expression. The gene discussed is SEPTIN4; the disease is early-onset autosomal dominant Alzheimer disease.