Although cancer predisposition has been remarkably described in its genetic causes, identifying the APC (MIM*611731) and the MCC Regulator of the WNT signaling pathway (MCC, MIM*159350) genes as the main ones responsible for the pathological phenotype [1,2,3,4,5], the genetic causes underlying ID in 5q interstitial deletions involving APC have never been investigated. The gene discussed is APC; the disease is cancer.