Choromosomal defects in general are lethal and the frequency of its occurrence at newly born babies is between 0,5%-07%. They often cause abortions in the period of the first 3 months of pregnancy. Numeric chromosomal irregularities have low repetition risks because of the creation of de novo. They have the risk of empirical repetition. However in pregnancies the risks observed in practice are less than those in theory.

Kromozomların yapısı