Analysis of clinical phenotypes of compound heterozygotes of Hb J-Bangkok and β-thalassemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze hematological characteristics of compound heterozygotes of Hb J-Bangkok and β-thalassemia, and to explore the influence of Hb J-Bangkok on the phenotype of β-thalassemia.</p><p><b>METHODS</b>Peripheral blood samples from a patient carrying Hb J-Bangkok and a β-thalassemia mutation, her family members and three sporadic Hb J-Bangkok carriers were collected. RBC analysis and hemoglobin electrophoresis were performed. Genotypes of α- and β-globin genes were analyzed.</p><p><b>RESULTS</b>The father of the proband and the three sporadic cases were single carriers of Hb J-Bangkok. All of them were asymptomatic and have normal hematological parameters except for an abnormal hemoglobin band detected on hemoglobin electrophoresis. The proband was a compound heterozygote for Hb J-Bangkok and β-thalassemia mutation IVS-Ⅱ-654. She presented typical β-thalassemia trait, featuring hypochromic microcytic anemia and increased Hb A₂ level. An abnormal hemoglobin band was also detected.</p><p><b>CONCLUSION</b>Carriers of Hb J-Bangkok alone are asymptomatic. Co-existence of Hb J-Bangkok and β-thalassemia may not aggravate the phenotype. Therefore, couples with one carrying Hb J-Bangkok and another carrying a β-thalassemia mutation do not require prenatal diagnosis.</p>

Hemoglobin J Rovigo (*53 ALA ==> ASP) is not associated with an *-globin gene deletion

Uma paciente de descendência italiana exibia uma hemoglobina anormal com migraçäo eletroforética rápida correspondendo a 30% do total de hemoglobina. A análise cromatográfica mostrou tratar-se de alteraçäo das cadeias *; pela digestäo trípica seguida de análise por HPLC foi identificada como Hb J Rovigo (* 53 Ala ==> Asp). A análise do DNA da paciente após a digestäo com enzima BamHI produziu um único fragmento de 14 kb. Esses resultados demonstram que a mutaçäo da Hb J Rovigo näo está associada à *-talassemia, ou seja, ocorre em um cromossomo 16 onde está presente um par de genes *

Fluorescence studies on the binding of reduced nicotinamide adenine dinucleotide phosphate to human hemoglobin A and its variant hemoglobin providence

The affinity constants for the binding of NADPH to human hemoglobin A were directly determined by fluorescence analyssis since nucleotide fluorescence is quenched on binding to the protein. The binding constants 6.1 x 10**5, 5.02 x 10**5 and 1.2 x 10**5 were found for deosyhemoglobin at pH 6.5, 7.0,respectively. Oxyhemoglobin does not bind NADPH significantly. These results are consistent with those found in oxygen-hemoglobin equilibrium experiments. The human hemoglobin variant, Providence-Asp, which has a marked decrease in 2,3 DPG affinity was also investigated. NADPH does not bind to the variant suggesting that the Lys B 82 residues is of fundamental importance to nucleotide binding and showing that the binding site is the same as that of 2,3 DPG or other organic polyphosphate, aloosteric modulators of hemoglobins. Experiments of inositol hexaphosphate (IHP)-NADPH site competition corroborate these results