The thalassaemia syndromes / D.J. Weatherall.

  • Weatherall, D. J.
Date:
1972
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: The thalassaemia syndromes / D.J. Weatherall. Source: Wellcome Collection.

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    CHAPTER 2 THE STRUCTURE AND SYNTHESIS OF HAEMOGLOBIN AND ITS GENETIC CONTROL In this chapter normal erythropoiesis and the structure and synthesis of haemoglobin will be reviewed in order to form a basis for subsequent chapters on abnormal haemoglobin synthesis in thalassaemia. Only those aspects of haemoglobin synthesis which have particular application to the thalassaemia problem will be considered in any detail and for further information the reader is referred to several more extensive reviews (Baglioni, 1963a; ItanOj 1965; Huehns and Shooter, 1965; Lehmann and Huntsman, 1966; Weatherall and Clegg, 1969a; Giblett, 1969). Since haemoglobin synthesis is closely related to the development and production of red cells we shall start this chapter with a brief description of the control of erythropoiesis. THE KINETICS AND CONTROL OF NORMAL RED CELL PRODUCTION The anatomy of red cell production: the erythron The erythropoietic tissue of the bone marrow and the total circulating red cell mass can be considered as a single organ, which has been called the 'erythron'. The site of red cell production alters during development. In early embryonic life erythropoiesis begins in the primitive mesenchyme of the yolk sac but by 8 weeks the liver and spleen are the main blood- forming organs, while at birth bone marrow fills the long bones, carpals and tarsals, vertebrae and skull. In adult life the bone marrow is localised to the axial skeleton and the proximal long bones. These anatomical changes in the site of blood production have been reviewed in detail by Wintrobe (1967). It is now generally accepted that all the formed elements of the blood are derived from a primitive totipotential stem cell. A proportion of these cells become 'committed' to the production of the red cells although the nature of this step in differentiation is completely obscure. The overall 6