CIN may be intrinsic (constitutional), associated with germinal mutations in genes related to chromosomal segregation such as BUBR1 and BUB1B cause mosaic variegated aneuploidy [38], FANC genes in Fanconi anemia, or ATM in Ataxia Telangiectasia [39,40] these syndromes display CIN at the cellular level and an increased risk of cancer [37,41]. This evidence concerns the gene BUB1B and Ataxia-telangiectasia.