How Does Nondisjunction Cause Turner Syndrome?

Nondisjunction: Failure of paired chromosomes to separate (to disjoin) during cell division, so that both chromosomes go to one daughter cell and none go to the other. Nondisjunction causes errors in chromosome number, such as trisomy 21 (Down syndrome) and monosomy X (Turner syndrome).

Where does nondisjunction occur in Turner syndrome?

That means that the woman with Turner syndrome had to have obtained her sole X from her mother. She did not obtain a sex chromosome from her father, which indicates that nondisjunction occurred in him. The nondisjunction could have occurred at either M_I or M_II.

Does Turner's syndrome result from nondisjunction in meiosis?

Nondisjunction may occur during meiosis I or meiosis II. Aneuploidy often results in serious problems such as Turner syndrome, a monosomy in which females may contain all or part of an X chromosome. Monosomy for autosomes is usually lethal in humans and other animals.