What is the medical term meaning royal disease?

Answer 1

Hemophilia has been called the royal disease. It is an x-linked recessive disorder that was common in the British and Russian royal families.

Gout is the "royal ailment." It was caused by eating excessive amounts of red meat.

Answer 2

Royals often married other royals and after generations of doing that it was often a cousin or even aunt or uncle. Marrying/ producing baby's within your own gene pool causes defects & weakness to occur more often.

The Royals disease in Europe was Hemophilia, a condition that causes hemorrhage, bleeding and the inability to clot. Bruising and sever bleeding from the most minor cuts could cause illness & death.