The “Royal disease” that afflicted Queen Victoria’s family line was a severe form of haemophilia, according to a new study. The verdict was reached after genetic analysis of the bones of the wife and children of the last Russian Tsar, Nicholas II, who were descendants of the British monarch.

Tsarina Alexandra, Queen Victoria’s granddaughter, and two of her children, Crown Prince Alexei and his sister Anastasia, all carried genetic mutations associated with the condition, also known as Christmas disease, after Stephen Christmas, the first sufferer to be studied in detail, in 1952.

The genetic defects responsible for haemophilia are located on the X chromosome, meaning that while women can be carriers of the faulty gene they are rarely sufferers. Females have two X chromosomes, so if there is a mutation on one they have a back-up. Men are XY, so if they inherit a faulty X chromosome they are guaranteed to develop the condition.

The analysis, published today in the journal Science, found that Alexandra carried a faulty gene linked to the production of a blood-clotting agent on one of her X chromosomes. Both her children inherited the defect, meaning that Alexei was a sufferer and Anastasia a carrier of the disease.

Haemophilia lowers the level of the chemicals that cause blood to clot after injury. Haemophilia A, resulting from a lack of clotting factor VIII, is the most common form, affecting one in 5,000–10,000 males. Haemophilia B, caused by a deficiency of factor IX, occurs in one in 20,000–34,000 male births. For severe haemophiliacs even an insignificant scratch can result in blood loss lasting days, weeks, or permanently. Such continual bleeding can be fatal if it occurs in the brain or inside joints. The nature of the gene defect carried by Alexandra and her children suggests a severe form of haemophilia B.

Today, patients are given synthetic replacements of the clotting agents. But in 1905 Tsarina Alexandra turned for help to Rasputin, the psychic peasant healer. His reputed mystical powers proved to be a foot in the door for higher ambitions. During the First World War he became the Tsarina’s personal adviser. His influence, which included handpicking candidates for government office, contributed to the 1917 Russian Revolution.

The bones of Russian siblings were found in the Urals in 2007. Evgeny Rogaev, of the University of Massachusetts Medical School and lead author of the study, was asked by Russian officials to examine the bones’ DNA to establish whether they belonged to the “missing” children of Nicholas II, whose family was murdered in 1918.

After determining that they were the remains of Alexei and Anastasia, Mr Rogaev and his team realised that they could use the data to investigate the nature of the “Royal disease”.

The haemophilia gene appears to have stemmed from a spontaneous mutation carried by Queen Victoria. Through two of her five daughters (Princess Alice and Princess Beatrice), Victoria passed the mutation to royal houses across the Continent, including the royal families of Spain, Germany and Russia. Leopold, Victoria’s son, died at 30 from bleeding after a fall.

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