Answer:
There are a number of potential causes of King Tut's death. While preliminary investigation suggested that he was killed by murder, more precisely blunt force trauma applied by General Horemheb, a man of low origin who became one of the king's closest advisors. However, a newer theory based on a fracture found on his left leg suggests that he may have been killed from a broken leg. Another ever-present theory for his death was that it was from the gradual effects of incest. The royal families of ancient Egypt intermarried extremely often, and even King Tut married his own sister. As such, there were a massive number of genetic diseases rampant among the royal families.
Hope it helps :)