Screening sperm donors for cystic fibrosis

EDITOR,—Cystic fibrosis is the most common serious autosomal recessive condition in white populations, affecting about 1 in 2500 live births, and until recently life expectancy rarely exceeded 30 years. The most common cystic fibrosis mutation (δF508, accounting for about 80% of two million British carriers), is a 3-bp deletion in a transmembrane protein cystic fibrosis transmembrane regulator gene. The next most common three or four mutations account for a further 5% of carriers.

One in 25 white people carries cystic fibrosis. As carriers are unaffected, individuals are often unaware until …