page_title: Haemophilia in European royalty
hierarchical_section_title: Haemophilia in European royalty
caption_attribution_description: English: Haemophilia in the descendants of Queen Victoria
context_page_description: Haemophilia figured prominently in the history of European royalty in the 19th and 20th centuries. Britain's Queen Victoria, through two of her five daughters, Princess Alice and Princess Beatrice, passed the mutation to various royal houses across the continent, including the royal families of Spain, Germany and Russia. Victoria's son Prince Leopold, Duke of Albany, also suffered from the disease. For this reason, haemophilia was once popularly called "the royal disease". Tests on the remains of the Romanov imperial family show that the specific form of haemophilia passed down by Queen Victoria was probably the relatively rare Haemophilia B.
  The sex-linked X chromosome disorder manifests almost exclusively in males, even though the genetic mutation causing the disorder is located on the X chromosome and can be inherited from the mother by male children or from either mother or father by female children. This is because the trait is recessive, meaning that only one correctly-functioning copy of the blood clotting factor gene is necessary for normal clotting. Females have two X chromosomes, and hence redundant copies of the blood clotting factor gene located on them.
context_section_description: Haemophilia figured prominently in the history of European royalty in the 19th and 20th centuries. Britain's Queen Victoria, through two of her five daughters, Princess Alice and Princess Beatrice, passed the mutation to various royal houses across the continent, including the royal families of Spain, Germany and Russia. Victoria's son Prince Leopold, Duke of Albany, also suffered from the disease. For this reason, haemophilia was once popularly called "the royal disease". Tests on the remains of the Romanov imperial family show that the specific form of haemophilia passed down by Queen Victoria was probably the relatively rare Haemophilia B.
  The sex-linked X chromosome disorder manifests almost exclusively in males, even though the genetic mutation causing the disorder is located on the X chromosome and can be inherited from the mother by male children or from either mother or father by female children.  This is because the trait is recessive, meaning that only one correctly-functioning copy of the blood clotting factor gene is necessary for normal clotting.  Females have two X chromosomes, and hence redundant copies of the blood clotting factor gene located on them.  A female who inherits a mutated copy on one X chromosome has also inherited a second X chromosome from the other parent that is likely to carry a non-mutated copy of the gene, capable of directing appropriate clotting.  Such a female, with normal clotting but possessing a single mutated copy of the gene, is called a carrier.  Males only possess a single X chromosome, inherited from their mother, having received a Y chromosome from their father instead of a second X.  If their sole X chromosome contains the haemophilia mutation they possess no second copy to provide for normal function, as in carrier females.  Each child of a carrier will have a 50% chance of inheriting their mother's mutation, of being a haemophiliac (sons) or carrier (daughters).  The daughter of a male haemophiliac will always inherit his mutation, while a son cannot ever inherit it.  A female will only be affected with haemophilia in the rare circumstance that she inherits mutated X chromosomes from both a haemophiliac father and a carrier mother.  No case of such double inheritance is known among Queen Victoria's descendants.
  Although an individual's haemophilia can usually be traced in the ancestry, in about 30% of cases there is no family history of the disorder, and the condition is speculated to be the result of spontaneous mutation in an ancestor.  Victoria's appears to have been a spontaneous or de novo mutation, most likely inherited from one of her parents, and she is usually considered the source of the disease in modern cases of haemophilia among her descendants. Queen Victoria's father, Prince Edward, Duke of Kent, was not a haemophiliac, but the mutation may have arisen as a germline mutation within him. The rate of spontaneous mutation is known to increase with paternal age (and is higher in fathers than in mothers at all ages); Victoria's father was 51 at her birth. The probability of her mother having had a lover who suffered from haemophilia is minuscule given the low life expectancy of 19th-century haemophiliacs.  Her mother, Victoria, Duchess of Kent, was not known to have a family history of the disease, although it is possible that she was a carrier, but among her children only Victoria received the mutated copy.
  Queen Victoria's eldest daughter, Victoria, Princess Royal, apparently escaped the haemophilia gene as it did not appear in any of her matrilineal descendants. Victoria's fifth child, Helena, may or may not have been a carrier; two healthy sons survived to adulthood, but two other sons died in infancy and her two daughters did not have issue. Victoria's sixth child, Louise, died without issue. Queen Victoria's sons Edward, Alfred, and Arthur were not haemophiliacs; however, her daughters Alice and Beatrice were confirmed carriers of the gene, and Victoria's son Leopold was a sufferer of haemophilia, making his daughter Princess Alice, Countess of Athlone a 
caption: Queen Victoria's family members with haemophilia
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