PTEN and juvenile polyposis syndrome: CNVs have been implicated in the development of many forms of CRC, e.g., germline deletion of two genes, PTEN and BMPR1A have been identified to be the cause of Juvenile Polyposis (JP) in four unrelated children [17], while genomic deletions in the genes SMAD4, BMPR1A and PTEN result in JP [18] and furthermore, the Leiden Open Variation Database (LOVD) database lists nearly 3,000 mutations in four MMR genes associated with HNPCC, of which many are gains and losses of genomic material [19].