Gene mapping in cystic fibrosis and its clinical applications.

Current techniques in molecular genetics have permitted the localisation of the mutation causing cystic fibrosis to chromosome 7q31, and allowed isolation of very tightly linked markers. It is possible to offer early prenatal diagnosis, carrier testing, and alteration of risk of unaffected partners in most cases. However, community-wide definitive carrier testing and new methods of treatment await the isolation of the gene.