The Cystic Fibrosis Connection

Cystic fibrosis is a life-altering, incurable (but treatable) genetic disease which causes premature death (by age 31 years) in approximately half of the people who are born with it. Cystic fibrosis (CF) primarily affects the lungs and the pancreas. What does this have to do with trying to get pregnant? More than most people think -- read on.

In addition to the concerns that long-time survivors of CF must address regarding their natural desires to have children (nearly all males with CF are infertile, and women's fertility may be decreased), a significant number of men without CF who are experiencing infertility may be doing so due to their having a mutation in the gene which causes CF (the gene is referred to as CFTR). While these men can now be assisted in their reproductive efforts via microsurgical epididymal sperm aspiration and intracytoplasmic sperm injection (MESA and ICSI), there is a significant 25% chance of such ART resulting in children with CF.

Researchers at the University of North Carolina at Chapel Hill have learned that minor mutations in the CF gene can cause several other conditions, including congenital bilateral absence of the vas deferens
"If a man with CBAVD and a healthy woman who donates an egg for an IVF procedure each carry a key CFTR mutation, there's a 25% chance the resulting child will develop cystic fibrosis."
(CAVD or CBAVD), a cause of approximately 1% to 3% of male infertility, and testicular impairment. In CAVD, some or all of the ducts necessary (epididymis, vas, and seminal vesicle) for a male to reproduce are missing, making it impossible for sperm to be adequately transported. It is recommended that men with CAVD undergo both trans-rectal ultrasound (TRUS) and renal ultrasound, in addition to CF testing, as a large percentage of men with CAVD will also be found to have upper urinary tract and renal malformations. As mentioned before, the most recent advances in ART for men with CAVD are MESA and ICSI. A less high-tech surgical correction, microscopic reconstruction of vas, is also available to these men and was determined by this study to be a cost-effective method of assisted reproduction.

Another part of the problem is that current screening methods for cystic fibrosis are far less adequate than originally believed, leaving a large percentage of affected men undiagnosed and increasing the risk of their passing the genetic disease on to their offspring. Dr. Keith Jarvi, who recently led a large study on the issue, advises that while current screening measures are "adequate" for general populations, more care should be taken with patients (men and women) seeking assistance for infertility. Preimplantation screening (determining the genotype of an egg before fertilization or of an embryo prior to implantation) may also be encouraged and sometimes required.

Researchers and physicians agree that for men with obstructive azoospermia (complete lack of sperm due to physical obstruction) and severe oligozoospermia (a reduced number of sperm), analysis of the CFTR gene mutations and screening of their female partners is critical prior to IVF procedures. The National Institutes of Health (NIH) in the U.S. released their consensus statement on the genetic testing for CF in April 1997, including their opinion on the optimal practices for CF testing.

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