ABSTRACT
When portions of two or more chromosomes exchange places, but the total amount of genetic material remained unchanged, the rearrangement is called a balanced translocation (Fig. 1.2). About 1 in 500 healthy individuals carries a balanced chromosome rearrangement. Carriers of balanced chromosome rearrangements, although healthy, are at risk of passing the rearrangement on to their offspring in an unbalanced fashion. Unbalanced chromosome rearrangements are characterised by a deficit or excess of genetic material. Pregnancies affected with structural chromosome rearrangements have an increased risk of miscarriage.
