Prenatal diagnostic options in cystic fibrosis.

There are currently two diagnostic options in cystic fibrosis. These involve assays for certain microvillar enzyme activities in amniotic fluid and recombinant deoxyribonucleic acid studies of markers linked to the cystic fibrosis gene on chromosome 7. The former are reduced in cystic fibrosis homozygotes; the latter make it possible to determine the particular pattern of chromosome 7 markers predictive of a cystic fibrosis homozygote in a specific family. However, neither test is appropriate for, applicable to, or informative in all families. The problems and potential of each approach are discussed.