Human genetics and medicine / by Cyril A. Clarke.

  • Clarke, Cyril A. (Cyril Astley)
Date:
1970
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Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Human genetics and medicine / by Cyril A. Clarke. Source: Wellcome Collection.

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    Sex (X)-Linked Inheritance 2 2.1 Haemophilia as an example of sex-linked recessive inherit¬ ance Haemophilia is an anomaly of blood coagulation (clotting) inherited as a sex-linked recessive, and is the disease which created such havoc in the royal families of Europe when introduced into them by the daughters and descendants of Queen Victoria (see Fig. 2-1). Haemorrhage, usually follow- 0- Queen Victoria of England О П Ш ж □-r¿ÍDr¿á¿á 2> Emperor Frederick Ш of Germany King EdwэrdШ[ of England Leopold of Albany U-r^ i (brG Frederick of Hesse 0- Tsar Nicholas Я of Russia É Ú É (5 a a AlfonsoXffi Leopold of Maurice of of Spain Battenburg Battenburg Waldemar Henry of Prussia of Prussia Tsarévitch Alexis of Russia è Ú (i) ú É Rupert Alfonso of Spain Gonzalo of Spain О Normal woman 0 Carrier woman □ Normal man ■ Affected man Fig. 2-1 Sex-linked recessive inheritance. Pedigree of haemophilia in the royal families of Europe. All affected individuals trace ancestry to Queen Victoria of England, who undoubtedly was a carrier. Her father was normal, nothing suggests that her mother was a carrier, and therefore Queen Victoria seems to have received a new mutant allele from one of her parents. It will be realized that many individuals in later generations are not included—among them our own royal family, who are quite free, being descended from an unaffected male. All Queen Victoria's children are entered in the pedigree. (By courtesy of Professor Curt Stem and Messrs Freeman.) ing injury but sometimes spontaneous, is the essential symptom. The bleeding is of the nature of a persistent, slow oozing which is out of all proportion to the extent of the injury; this can last for weeks and may lead to profound anaemia. Cases also often present as orthopaedic problems due to recurrent haemarthroses (bleeding into the joints). The disease usually appears in early childhood or even in infancy, and it is due to the deficiency