Cytogenetics is a field of study which analyzes the number and structure of human chromosomes. Changes that affect the number and/or structure of the chromosomes can cause problems with fertility, growth, development, and how the body functions. Chromosomal abnormalities can happen when egg and sperm cells are being made, during early fetal development, or after birth in any cell in the body. Changes in chromosome structure can disrupt genes, causing the proteins made from disrupted genes to be missing or faulty. Depending on size, location, and timing, structural changes in chromosomes can lead to infertility, birth defects, syndromes or even cancer. Alternatively, some chromosomal changes may have no effect on a person’s health.
The analysis of chromosomes is strongly recommended during the diagnostic workup in patient with azoospermia, severe oligozoospermia, primary ovarian dysfunction or recurrent fetal loss. In these subjects the cytogenetic screening is mandatory prior to any ART procedure (including intrauterine insemination, IUI). Karyotype analysis should be included as diagnostic test, when no result is achieved after 1 year of sexual intercourse aimed at pregnancy.