Who Discovered Cri Du Chat? The person who discovered Cri Du Chat was a French scientist named Dr. Jerome Lejeune. He was born on June 13, 1926 and died on April 3,1994 at the age of sixty-seven. This was because he smoked and was diagnosed with lung cancer. During his lifetime, Lejeune discovered a number of genetic disorders, including Cri Du Chat. Another disorder he discovered was a Down Syndrome. In 2013, Dr. Jerome Lejeune's discovery of Cri Du Chat was celebrated.