Human germline PTEN mutations or conditional deletions of PTEN in mice have provided insights into possible causes associated with neurological disorders such as macrocephaly, ataxia, seizures, mental retardation, and autism (Backman et al., 2001; Kwon et al., 2006; Van Diepen and Eickholt, 2008; Zhou and Parada, 2012). The gene discussed is PTEN; the disease is cerebellar ataxia.