Haemoglobin abnormalities

Jonxls, J. H. P. and Hulsman, T. H. J. "A Laboratory Manual on Abnormal Haemoglobins", Second Edition, Blackwell, Oxford, 1968. 

The blood of the patients with thalassaemia contains an abnormal form of haemoglobin. 

Other variations may produce haemoglobins which are less stable than usual and sometimes substitutions may produce no detectable abnormalities. 

DFOA has been examined for ability to inhibit chronic inflammation. In a preliminary study with rheumatoid patients, intramuscular DFOA (1 g) produced an abrupt rise in haemoglobin, a response which was taken to indicate suppression of inflammation77. Under this regime no ill effects were observed but this was not the case where rheumatoid patients received 3 g d 1 for 5 days each week over 1 to 3 weeks78. Out of seven patients ocular abnormalities were induced in four of them but subsided on termination of DFOA treatment. Further complications of DFOA therapy were observed with two patients who lapsed into unconsciousness for up to 72 hours when they were placed upon a course of treatment with phenothiazine, a treatment initiated to suppress DFOA-induced nausea. 

Examination showed that her lower abdomen was a little distended and very tender, but there were no other abnormalities. Her blood pressure was low at 102/70 mmHg and her temperature slightly raised at 38.5 °C. A blood sample showed normal haemoglobin and red cell number, but a raised white blood cell count. No intestinal obstruction showed on an X-ray of her abdomen. In view of her symptoms and age, a provisional diagnosis of diverticulitis was made. 

Blood gas tensions are usually abnormal arterial PO2 is lower and arterial PC02 higher than normal. Patients may be cyanosed because of an increase in reduced (deoxygenated) haemoglobin in the tissues. 

While simple blood smears can help with diagnosis of HbS, abnormal haemoglobins resulting in other haemoglobinopathies can be investigated by comparing... 

Figure 3.11 Investigation of abnormal haemoglobin (HbS). Part B figures reproduced from the Encyclopaedia Britannica online (www.britannica.com).

It is interesting to note that in a number of abnormal haemoglobins (haemoglobin M) where amino acid substitution at or near the haem results in a permanent oxidation of the iron to the ferric state, departures from axial symmetry are sometimes seen. In two cases (haemoglobin M Hyde Park and haemoglobin M Milwaukee) in which the defect is in the /3 chain, the rhombic distortion of the iron of the /3 chain is dependent upon the degree of oxygenation of the a chains [2, 7]. 

AlO. Allan, N., Beale, D., Irvine, D., and Lehmann, H., Three haemoglobins K Woolwich, an abnormal, Cameroon and Ibadan, two unusual variants of human haemoglobin A. Nature (London) 208, 658-661 (1965). 

B5. Baglioni, C., and Ingram, V. M., Abnormal human haemoglobins. V. Chemical investigation of haemoglobins A, G, C, X from one individual. Biochim. Biophys. Acta 48, 253-265 (1961). 

H62. Hunt, J. A., and Lehmann, H., Abnormal human haemoglobins. Haemoglobin Bart s a foetal haemoglobin without a-chains. Nature London) 184, 872-873 (1959). 

L22. Lie-Injo, L. E., and Lie Hong, G., Abnormal haemoglobin production as a probable cause of erythroblastosis and hydrops foetalis in uniovular twins. Acta Haematol. 25, 192-199 (1961). 

M27. Morimoto, H., Lehmann, H., and Perutz, M. F., Molecular pathology of human haemoglobin stereochemical interpretation of abnormal oxygen affinities. Nature (London) 232, 408-413 (1971). 

W8. Weatherall, D. J., Abnormal haemoglobin in the neonatal period and their relationships to thalassaemia. Brit. J. Haematol. 9, 265-277 (1963). 

Normal haemoglobin has a Pjg of 3.4 kPa and n of 2.6-3.0 at pH 7.4. Values of both P50 and n are affected by genetic abnormalities in haemoglobin synthesis that alter the amino acid sequence. Over 190 such variants are known, with a wide range of Pjg and n values. 

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