Proteins 45 



and cell proteins are known to exist, but their significance is still 

 obscure (Miller and Miller, 1947; Hultin, 1956; Novikoff, 1957; 

 Grant and Rees, 1957) . 



HAEMOCHROMATOSIS 



This is a genetically determined disease in which the basic dis- 

 order is an abnormally high level of absorption of iron with subse- 

 quent deposition of an iron-protein complex in liver, skin, pancreas 

 and elsewhere. The iron-protein complex resembles but is not 

 identical with, haemosiderin. There is extensive damage to the 

 affected organs, partly due to cell death and replacement fibrosis, 

 partly due perhaps to a toxic action of iron on glycolysis, triose 

 phosphate dehydrogenase being especially vulnerable to the damag- 

 ing effects of iron ions. 



The absorption of iron from the intestine is governed normally 

 by a system of proteins. The first of these, apoferritin, is present in 

 the mucosal epithelium and complexes with iron in the bowel con- 

 tents to form the second protein, ferritin. Depending on the body's 

 needs, ferritin gives up its iron to a third protein, transferrin, that 

 transports iron in the blood stream. Normally, when all the apoferri- 

 tin in the bowel mucosa has combined with iron, absorption of the 

 metal ceases. In haemochromatosis, however, the mechanism is dis- 

 torted and iron continues to be absorbed so that the blood trans- 

 ferrin is permanently saturated with iron. The precise nature of the 

 disturbance has yet to be identified. It seems likely, however, that 

 the defect lies in the transfer of iron from ferritin to transferrin 

 probably due to congenital absence of some regulating factor. 



It is possible that in addition to the above abnormalities, pa- 

 tients suffering from haemochromatosis exhibit a more general 

 nutritional defect which may contribute to the pathology of the 

 condition, notably hepatic fibrosis. Animal experiments indicate 

 that protein metabolism may also be concerned in this aspect of 

 the disease together perhaps with a relative choline deficiency. 



HEPATOLENTICULAR DEGENERATION 



This is a genetically determined disease with some similarities 

 to haemochromatosis. Copper is normally transported in the body 



