Prospects for gene therapy now and in the future.

Advances in gene technology and cell biology have supplied the means to undertake human gene therapy in the near future. Techniques have been developed for the efficient introduction of gene sequences into the pluripotential stem cells of the haematopoietic system and our increased understanding of gene-regulatory mechanisms should allow therapeutic gene expression levels to be obtained. Gene therapy should, at present, be termed gene supplementation since it will involve the addition of corrective genes to the host cell genome. It may only be used to treat recessively inherited disorders. Prospects for the future include the use of homologous recombination to correct or replace defective genes, allowing the treatment of dominantly inherited diseases.