| Citation | Distinguished for his pivotal role in the discovery of the gene responsible for cystic fibrosis, a major genetic disorder affecting 1 in every 2,500 Caucasian newborns of European origin. Lap-Chee Tsui first demonstrated that the gene for this disorder is located on the long arm of human chromosome 7. By isolating recombinant DNA representing this region of the human chromosome, he located the gene that is defective in individuals affected with cystic fibrosis and identified the mutations that give rise to the majority of cases. This achievement represents the first time a gene for an autosomal recessive disorder was defined using reverse genetics. The isolation of the cystic fibrosis gene has provided a means for identifying carriers and for prenatal diagnosis of this disorders [sic]. It has also paved the way for the elucidation of the pathophysiology of cystic fibrosis through direct analysis of the novel protein, and for the development of new therapeutic approaches. |