Moreover, PGD can be used to identify cancer predispositions as ataxia-telangiectasia, familial adenomatous polyposis, familial colorectal cancer, breast cancer (BRCA1 and BRCA2), von Hippel-Lindau syndrome, retinoblastoma, neurofibromatosis types 1 and 2, Gorlin syndrome, tuberous sclerosis, and familial posterior fossa brain tumors [32]. Here, BRCA1 is linked to familial colorectal cancer.