Nondisjunction is the the failure of homologous chromosomes of chromatids to segregate during meiosis or mitosis. Nondisjunction can result in cancer. Nondisjunction during meiosis results in one daughter cell having both a pair of parental chromosomes with the other having none. It causes mutation in the number of chromosomes, either extra chromosomes or missing chromosomes. Nondisjunction during meiosis can cause chromosomal disorders such as trisomy 21 (down Syndrome), Turner's Syndrome, and Klinefelter's Syndrome.