Haemoglobin Pierre-Benite - a high affinity variant associated with relative polycythaemia

Abstract

This is the second reported example of Hb Pierre--Benite (beta90 Glu-->Asp). This mutation is associated with increased oxygen affinity and polycythaemia. No instability was found and there was no charge shift detected by cellulose acetate electrophoresis at pH 8.3. The mutation was however, clearly indicated by electrospray ionization mass spectrometry (ESI MS), which showed an abnormal beta chain with a 14 Da decrease in mass. Blood volume studies documented a relative rather than a true polycythaemia and this finding has been reported in at least two other high affinity haemoglobin variants--Hb Heathrow and Hb Rahere. This finding led to delay in diagnosis because high oxygen affinity variants are conventionally considered to cause a true polycythaemia.

Identification of high oxygen affinity hemoglobin variants in the investigation of patients with erythrocytosis

“…The Santa Clara variant cannot achieve the T state 9 while Pierre-Benite is thought to stabilize Hb in the T quaternary structure 8,11 and Hb Olympia 12 affects the surface of the protein causing it to self-associate. Other mutations cause structural alteration of the hemepocket.…”