Cystic fibrosis related infertility (CF carrier)
Cystic fibrosis is the clinical expression of a decrease in the CFTR protein made from chromosome number 7. This same protein deficiency also prevents the formation of the vas deferens. As a result the testicle is making normal sperm but it cannot be transported into the ejaculate resulting in a semen analysis reporting no sperm present. Since the sperm in the testicle are normal pregnancies are achieved by retrieving sperm surgically and placing them into the egg using in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). The important test to perform in this male diagnosis is a cystic fibrosis screen for the wife. If she carries the same defect on one of her number 7 chromosomes then there is a 25% chance of offspring having cystic fibrosis.