Continuing our discussion of inbreeding from yesterday's post: human inbreeding doesn't always occur in the backwoods – sometimes it takes place in palaces. Let's try to find some examples of royal personages who suffered from inbreeding depression.
In the 4th dynasty (c. 2600-2450 BC ?), Khufu (aka "Cheops"), the pharaoh who most scholars believe built the Great Pyramid of Giza, had a wife named Meritites who was maybe his sister (or half-sister). Khufu's father Sneferu and his mother Hetepheres are also believed to have both been children of the pharaoh Huni. Khufu's son and successor Djedefre married his (probably half) sister Hetepheres who had previously been married to another brother or half-brother named Kawab with whom she produced a daughter, the future queen Meresankh.
Looking ahead to the 18th dynasty (c. 1550-1300 BC ?), Thutmosis II was married to his sister Hatshetsup with whom he had a daughter (his "son and heir" Thutmosis III was the child of a lesser wife or concubine). Thutmosis IV's second queen, Iaret, was probably his sister although again she was not the mother of his son and successor Amenhotep III. Finally, the famous King Tutankhamun's wife Ankhesenamen was probably either his half-sister or his niece. Also, DNA tests administered on the mummies of 18th-dynasty royals appear consistent with the genealogical accounts gleaned from inscriptions, including the marriages between close relatives.
Image: photo of Great Pyramid by flckr user romsrini taken from Sacred-Destinations.com and subject to Creative Common license; photo of coin of Ptolemy Philadelphos & Arsinoe taken by Matthias Kabel from Pergamommuseum in Berlin; Ptolemy genealogy by Muriel Gottrop is in the Wikipedia Commons.