Genotyping of cystic fibrosis families with linked DNA probes.

Forty-six British families, containing at least one child affected with cystic fibrosis, were typed for restriction fragment length polymorphisms (RFLPs) by the probes pmet H, pmet D, pJ3.11 and 7c22. Thirty-five (76%) were fully informative for prenatal diagnosis and carrier detection, while in the remainder prenatal exclusion of an affected fetus could be carried out in half the pregnancies. The frequencies of individual alleles did not differ between cystic fibrosis and normal chromosomes. However, the previously noted excess of one haplotype on chromosomes carrying the cystic fibrosis gene was confirmed.