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.
The phrase Happy Birthday did not appear on birthday cakes until the song Happy Birthday to You was popularized in the early 1900s. http://en.wikipedia.org/wiki/Birthday_cake. Before the domestication of electricity, candles were a common source of lighting, before, and later in addition to, the oil lamp.