24 March 2018
Int J Med Sci 2007; 4(4):232-236. doi:10.7150/ijms.4.232
Short Research Communication
Familial Polycythemia Caused by a Novel Mutation in the Beta Globin Gene: Essential Role of P50 in Evaluation of Familial Polycythemia
1. Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
Two polycythemic subjects from a family with multiple polycythemic subjects were evaluated. Estimation of oxygen affinity of Hb from venous blood gas parameters (P50) revealed low P50 suggesting a high affinity Hb variant. Further work up, which included beta globin gene sequencing, revealed a novel mutation changing a codon to the previously reported high affinity Hb - Hb Johnstown (beta109 Val->Leu). Polycythemic subjects with high affinity Hb variant are asymptomatic with normal life expectancy. Their differentiation from polycythemia vera (PV) is crucial to avoid therapy which is otherwise reserved for PV patients. We provide an electronic version (in Microsoft excel program) of a previously reported mathematical formula for rapid calculation of P50 from venous blood gases. Estimation of P50 is an essential initial step in the evaluation of a subject with personal and family history of polycythemia.
Keywords: High affinity Hb, Polycythemia, Estimation of P50
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How to cite this article:
Agarwal N, Mojica-Henshaw MP, Simmons ED, Hussey D, Ou CN, Prchal JT. Familial Polycythemia Caused by a Novel Mutation in the Beta Globin Gene: Essential Role of P50 in Evaluation of Familial Polycythemia. Int J Med Sci 2007; 4(4):232-236. doi:10.7150/ijms.4.232. Available from http://www.medsci.org/v04p0232.htm