RESUMO
Laboratory identification of hemoglobin (Hb) variants can involve multiple techniques. The use of semi-automated instruments that perform gel electrophoresis and staining, such as the SPIFE 3000 electrophoresis system, can greatly reduce the labor required for these commonly used techniques. We performed a comparison of the method involved in SPIFE 3000 system with those of manual gel electrophoresis. A total of 22 540 samples were analyzed using the SPIFE 3000, and compared with mobilities on cellulose acetate and citrate agar gels using standard manual methods. The results were compared using relative electrophoretic mobilities (REM). Of the 191 Hb variants identified, only 13 had REM that differed from manual electrophoresis when analyzed using the SPIFE 3000 system. One variant (Hb O-Indonesia) showed different mobility on both acid and alkaline gels, two (Hb E, Hb Sunshine Seth) on alkaline gel only, and 10 (Hbs N-Baltimore, N-Seattle, O-Arab, Shelby, Summer Hill, Tak, Hasharon, M-Iwate, Q-Iran, and Setif) on acid gels only. The SPIFE 3000 semi-automated electrophoresis system produces similar results when compared with those of standard manual electrophoresis methods.
Assuntos
Eletroforese/instrumentação , Eletroforese/métodos , Hemoglobinas/análise , Variação Genética , HumanosRESUMO
We report a novel mutation at alpha66(E15)Leu-->Pro (alpha2) (CTG-->CCG), that we have named Hb Dartmouth for the medical center at which the patients were cared for, in monozygotic twins who also inherited the Southeast Asian alpha-thalassemia-1 deletion. The mother, of Khmer ancestry, is heterozygous for alpha-thalassemia-1. The father, who is of Scottish-Irish ancestry, is a silent carrier of the codon 66 mutation. The twins had severe neonatal anemia requiring transfusion.
Assuntos
Anemia Neonatal/genética , Hemoglobinas Anormais/genética , Talassemia alfa/genética , Adulto , Substituição de Aminoácidos , Anemia Neonatal/etiologia , Camboja/etnologia , Análise Mutacional de DNA , Saúde da Família , Feminino , Hemoglobinas Anormais/efeitos adversos , Humanos , Recém-Nascido , Masculino , Mutação Puntual , Gêmeos , Reino Unido/etnologiaRESUMO
Among the causes of life-long cyanosis are congenital methemoglobinemia due to M hemoglobins, congenital methemoglobinemia due to methemoglobin reductase deficiency, a small number of low oxygen affinity hemoglobins, and a small number of unstable hemoglobins that spontaneously form methemoglobin in vivo at an accelerated rate. We report an unstable hemoglobin with these characteristics that was observed in a family of indigenous (native American) origin living near Santiago, Chile. This variant has the substitution beta28(B10)Leu-->Met, unambiguously corresponding to the DNA mutation of CTG-->ATG in beta-globin gene codon 28.
Assuntos
Anemia Hemolítica/sangue , Hemoglobinas Anormais/genética , Metemoglobinemia/sangue , Anemia Hemolítica/induzido quimicamente , Anemia Hemolítica/genética , Hemoglobinas Anormais/metabolismo , Humanos , Leucina , Masculino , Metemoglobinemia/genética , Metionina , Azul de Metileno , Pessoa de Meia-Idade , Mutação Puntual , SulfonamidasRESUMO
OBJECTIVE: To determine the nature and characteristics of a unique hemoglobin variant that causes a spurious increase in glycated hemoglobin (HbA1c). MATERIAL AND METHODS: Blood specimens from four unrelated persons with this hemoglobin variant were examined by conventional laboratory methods, including electrophoresis, high-performance ion-exchange chromatography, and isoelectric focusing; by amino acid sequence analysis, polymerase chain reaction-based DNA sequence analysis, and electrospray ionization mass spectrometry, to establish the molecular structure; and by studies of oxygen affinity under varied conditions, to define the functional characteristics of the hemoglobin variant. RESULTS: The unique hemoglobin variant observed in these four cases is due to the mutation CAC-->TAC, at beta-globin gene codon 143, corresponding to beta 143 (H21) His-->Tyr. This amino acid substitution affects an important 2,3-diphosphoglycerate binding site and slightly increases the oxygen affinity of the hemoglobin variant. CONCLUSION: A hitherto unrecognized hemoglobin variant, encountered in four unrelated persons of Irish or Scots-Irish ancestry, hemoglobin Old Dominion/Burton-upon-Trent, beta 143 (H21) His-->Tyr, has now been characterized at the molecular, structural, and functional levels. Although it is associated with a slight increase in oxygen affinity, it is without hematologic effect, and its only clinical significance is that it coelutes with HbA1c on ion-exchange chromatography and thereby causes a spurious increase in HbA1c and compromises the use of this analyte to monitor the treatment of diabetes mellitus.
Assuntos
Diabetes Mellitus/sangue , Hemoglobinas Glicadas , Adulto , Idoso , Diabetes Mellitus/etnologia , Feminino , Hemoglobinas Glicadas/genética , Humanos , Irlanda/etnologia , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Escócia/etnologiaRESUMO
Three cases are reported of Hb S/Hb Lepore combination with very mild sickling manifestations. The presence of a nonalpha-chain variant with a high proportion of delta chain sequences, including 22 ala, appears to ameliorate sickle-cell disease. Efforts to increase the proportion of Hb A2 may be beneficial in sickle-cell disease.