Which famous diarist had a sister named Margot?

Margot Betti Frank (February 16, 1926 – February 1945) was the eldest daughter of Otto Frank and Edith Frank and the older sister of Anne Frank. Margot's deportation order from the Gestapo hastened the Frank family into hiding. According to the diary of her younger sister, Anne, Margot kept a diary of her own, but no trace of Margot's diary has ever been found. She died in Bergen-Belsen.

Annelies Marie "Anne" Frank (12 June 1929 – February or March 1945) was a German-born diarist. One of the most discussed Jewish victims of the Holocaust, she gained fame posthumously following the publication of The Diary of a Young Girl (originally Het Achterhuis; English: The Secret Annex), in which she documents her life in hiding from 1942 to 1944, during the German occupation of the Netherlands in World War II. It is one of the world's most widely known books and has been the basis for several plays and films.