Screening for cystic fibrosis: medical and ethical issues

Abstract

Cystic fibrosis (CF) is one of the most common severe, recessively inherited diseases in the Caucasian population. With the identification of the gene and the most common mutations responsible for the condition”‘, carrier screening has become a real option to be considered by the families of sufferers, the public at large, health planners and policy makers. In the UK, approximately 1 in 25 individuals are carriers and therefore, there is a 1 in 625 chance of two carriers marrying. If both parents are carriers, there is a 1 in 4 risk of each child inheriting both CF alleles and being affected. The birth incidence of CF is around 1 in 25003. Affected individuals have a variety of clinical problems which are dominated by recurrent respiratory tract infections (often with Pseudomonas species) associated with viscid, inspissated mucus, failure to thrive secondary to a lack of pancreatic secretions reaching the gut (85%) and, occasionally, meconium ileus presenting in the newborn period (5510%). Infertility is found in most adult males with CF and is frequent in females. The prognosis for CF has improved in recent years with a current median age of survival of 25 years. It has been estimated that the median survival of CF children born in 1990 may even be as high as 40 years if current trends continue4. The management of CF includes physiotherapy (chest percussion) to aid clearance of infected secretions, antibiotic therapy to treat infection, pancreatic enzyme replacement with meals and snacks and nutritional supplementation. The cloning and identification of the gene and protein product defective in CF has allowed studies of new approaches to therapy, including the possibility of transferring a normal gene into airway epithelial