22q11.2 deletion syndrome is caused by the deletion of a small section of chromosome 22. It results in a cleft palate, heart defects, autoimmune disorders, and more. The symptoms vary wildly and can be accompanied by learning disabilities and mental illness. Cystic fibrosis is caused by a point deletion.
The melody of Happy Birthday to You comes from the song  Good Morning to All , which has been attributed to American siblings Patty Hill and Mildred J. Hill in 1893, although the claim that the sisters composed the tune is disputed.
Interesting information about the song. The song was popularized by Frank Sinatra. Its lyrics were written by Paul Anka and set to music based on the French song Comme d'habitude composed in 1967 by Claude FranÃ§ois and Jacques Revaux. Anka's English lyrics are unrelated to the original French song.