Professor Tsui also contributed to the fight against the SARS coronavirus during its outbreak in 2003, and, led the Hong Kong consortium in the international effort (the HapMap Project) in completing the first comprehensive catalogue of human genetic variations in 2005.

Prior to his appointment at HKU, Professor Tsui was Geneticist-in-Chief and Head of the Genetics and Genomic Biology Program of the Research Institute, at The Hospital for Sick Children in Toronto. He was also the holder of the H.E. Sellers Chair in Cystic Fibrosis and University Professor at the University of Toronto.

Born in Shanghai and raised in Hong Kong, Professor Tsui received his bachelor and master's degrees from The Chinese University of Hong Kong, and his Ph.D. degree from the University of Pittsburgh in 1979. After a brief training in the Oak Ridge National Laboratory, he joined the Department of Genetics at The Hospital for Sick Children. He received international acclaim in 1989 when he identified the defective gene that causes cystic fibrosis, which is a major breakthrough in human genetics. He has also made significant contributions to the study of the human genome, especially the characterization of chromosome 7, and, identification of additional disease genes. He has 300 peer-reviewed scientific publications and 65 invited book chapters and papers.

Professor Tsui is the recipient of many national and international prizes, and a Fellow of Royal Society of Canada, Fellow of Royal Society of London, Fellow of Academia Sinica, Foreign Associate of the National Academy of Sciences USA, Foreign Member of the Chinese Academy of Sciences, and Laureate of the Canadian Medical Hall of Fame, and the Founding President of the Academy of Sciences of Hong Kong. He has received many awards over the years, including 12 honorary doctoral degrees from universities around the world, the Order of Canada (Officer), the Order of Ontario, Knight of the Légion d'Honneur of France, the Gold Bauhinia Star and Justice of the Peace from the Hong Kong SAR Government.