unstable hemoglobins

un·sta·ble he·mo·glo·bins

a group of rare Hb's with amino acid substitutions (or amino acid deletions in three types) that alter the three-dimensional shape of the globin in a manner that renders the molecule unstable; they have an increased but variable tendency to autooxidation and Heinz body formation and are associated with congenital nonspherocytic hemolytic anemia. The unstable β-chain abnormalities include Hb's Genova, Gun Hill, Hammersmith, Köln, Philly, Sabine, Santa Ana, Sydney, Wien, and Zürich; unstable α-chain abnormalities include Hb's Bibba, Sinai, and Torino.
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
Unstable hemoglobins, hemoglobins with altered oxygen affinity, hemoglobin M, and other variants of clinical and biological interest.
Oxidative denaturation in congenital hemolytic anemias: the unstable hemoglobins. Semin Hematol.
However, unstable hemoglobins co-expressed with [alpha]-thalassemia minor can produce HbH disease in the same patient populations.
An interesting sickle cell compound heterozygote involving the unstable hemoglobin Volga produces a diagnostic dilemma.
Hb Sallenches [a104(GI 1) Cys>Tyr, TGC>TAC (a,2)]: an unstable hemoglobin variant found in an Indian child.
Two unstable hemoglobins are present in the blood and both have a higher affinity for oxygen than normal hemoglobin, resulting in poor oxygen delivery to tissues.
Sickle-cell anemia [Beta] globin Hemoglobin C disease [Beta] globin Hemoglobin SC disease [Beta] globin Hemoglobin E disease [Beta] globin Hemoglobin D disease [Beta] globin [Beta] thalassemias [Beta] globin [Alpha] thalassemias [Alpha] globin Hereditary persistence [Gamma] globin of fetal hemoglobin (HPFH) Hemoglobinopathies associated with [Alpha] chain predominantly unstable hemoglobins
Unstable hemoglobins, hemoglobins with altered oxygen affinity, hemoglobin M and other variants of clinical and biological interest.
Other possible causes include formation of methemoglobin due to medication (nitrate, dapsone, and so forth), enzymatic deficiency (deficiency in cytochrome [b.sub.5] reductase or cytochrome [b.sub.5]), Hb M anomalies, unstable hemoglobin variants, and easily oxidizable variants.
Impaired binding of AHSP to [alpha] chain variants: Hb Groene Hart illustrates a mechanism leading to unstable hemoglobins with [alpha] thalassemic like syndrome.
Hemoglobin Debrousse [[beta]96(FG3)Leu[right arrow]Pro]: a new unstable hemoglobin with twofold increased oxygen affinity.