The 'royal disease'--haemophilia A or B? A haematological mystery is finally solved.

'History can change blood. And blood can change the course of history'. Haemophilia is an illustration of this, as this congenital hereditary coagulation disorder, passed through the majority of royal European families at the beginning of the 20th century by Queen Victoria of England and Empress of the Indies, had indisputable political consequences, which led to one of the most defining moments of contemporary history: the Bolshevik Revolution. Today, none of Queen Victoria's living descendents carry haemophilia. Because of this, the characterization of haemophilia (deficit of either factor VIII or XI) and the identification of the causal mutation are rendered impossible. In 1991, a tomb containing the remains of Czar Nicolas II's entire family was discovered. A second tomb was discovered in 2007, allowing Russian and American scientists to fill in this gap in medical history. Following a scientific approach combining current genetic experimentation tools and the development of biological information technology, researchers were able to identify each body, allowing them to obtain precious genetic material from the young Czar Alexis, who was stricken by the disease, which revealed a causal substitution in the splice acceptor site of exon 4 in the F9 gene. This mutation that is responsible for haemophilia B had traumatized European royal families throughout the 20th century!