INSR and Tangier disease: Some examples of transgenic knockdown disease models include: an Abca1-deficient mouse line that mimics Tangier disease (Chang et al., 2004); insulin receptor (Insr)-knockdown mice that develop severe hyperglycemia within 7 days (Seibler et al., 2007); and the reversible knockdown of Trp53 as a model useful for tumor regression studies (Dickins et al., 2007).