Prince Leopold, Duke of Albany (1 on chart), the first of Queen Victoria's descendants to suffer from haemophilia was described as a delicate child who remained a constant source of anxiety to the Queen throughout his life, evidence exists that Leopold also suffered mildly from epilepsy, like his grand-nephew Prince John (the youngest son of King George V).

Since females have two X chromosomes, they are more often than not carriers. Males possess XY chromosomes and females XX. A recessive gene, it is carried on the sexual female chromosome X. The condition is passed on to males through females, who do not manifest the symptoms of the disease themselves. The blood of a haemophiliac cannot coagulate, due to the fact that one or more of the plasma proteins required to form a clot is absent or reduced in their blood. Haemophilia is an X-linked recessive disorder. Victoria and Albert and their eldest five children No earlier occurrence of the disease in the Royal family had been known, it is assumed that a mutation occurred in the sperm of the Queen's father, Edward Augustus, Duke of Kent. The first instance of haemophilia in the British Royal family occurred on the birth of Prince Leopold on 7th April 1853, Leopold was the fourth son and eighth child of Queen Victoria and Prince Albert of Saxe-Coburg-Gotha. Haemophilia acquired the name the royal disease due to the high number of descendants of Queen Victoria afflicted by it.

Queen victoria's ancestors family tree