Alpha-Thalassemia and fetal hemoglobin.
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Biomedical subjects
Publications and source records attributed to W B Qin.
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We have analyzed the quantities of alpha x chain-containing hemoglobins (alpha 2 x beta 2 and alpha 2 x delta 2) in 14 heterozygotes for Hb Q-India [alpha 64(E13)Asp-->His] or Hb Q-Thailand [alpha 74(EF3)Asp-->His]; both amino acid replacements are the result of mutations in the alpha 1-globin gene. Five of these persons (three with Hb Q-India and two with Hb Q-Thailand) had an additional beta(0)-thalassemia heterozygosity. The average quantities for Hb Q + Hb Q2 in the four groups were 17.2% (alpha alpha Q/alpha alpha; beta A/beta A), 9.5% (alpha alpha Q/alpha alpha; beta A/beta(0) Th), 26.8% (-alpha Q/alpha alpha; beta A/beta A), and 16.95% (-alpha Q/alpha alpha; beta A/beta(0) Th). These variations can best be explained by a posttranslational control mechanism; an imbalance in the alpha A, alpha Q, and beta A chain ratio will favor the alpha 2 Q beta 2 formation when an alpha-thalassemia is present and will reduce its formation in the presence of a beta-thalassemia heterozygosity.
We have sequenced the amplified beta-globin genes of five, apparently unrelated, Spanish adults with a fast-moving hemoglobin variant, and observed a GGC-->GAC mutation at codon 119 which identified the abnormality as Hb Fannin-Lubbock or alpha 2 beta (2)119(GH2)Gly-->Asp. In addition, we found a GTC-->CTC change at codon 111 which leads to a Val-->Leu replacement at this location. Protein analysis of the beta A and beta X chains from one of these individuals confirmed that both mutations are located on the same chromosome. It is hypothesized that some other known variants may carry an additional mutation in one of their exons, resulting in a silent amino acid substitution which may have an effect on some physicochemical property. In the case of Hb Fannin-Lubbock, it appears likely that the Val-->Leu replacement at beta 111, rather than the Gly-->Asp replacement of beta 119, is the cause of the instability of the variant. The Hb Fannin-Lubbock variant in these Spanish families had a normal oxygen affinity.
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Feminizing adrenocortical tumor is rare. Three patients with feminizing adrenocortical tumor (2 males and 1 female) were treated surgically. The age of the patients was 11, 21 and 32 years old respectively. The removed tumors weighing 70 g, 250g and 31g respectively and they all were adrenocortical adenoma. The chief symptoms of the patients were gynecomastia, orchiatrophy and sexual inadequacy. The results of follow-up for 1-11 years showed no recurrence in all 3 patients. We consider that the tumor should be resected as soon as the diagnosis was established and long-term follow-up should be made after operation.
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Several members of a large Caucasian family who presented with a congenital Heinz body hemolytic anemia were found to be carriers of the unstable Hb Bibba or alpha 2 136(H19)Leu-->Pro beta 2. Identification by protein analysis was hampered by the instability of the variant which complicated its isolation from shipped blood samples. Moreover, the detection of the CTG-->CCG mutation at codon 136 of the alpha 2 gene required the substitution of dGTP by dITP during the DNA sequencing process to prevent the occurrence of secondary structures and compressions in the sequencing gel. The first Hb Bibba heterozygote, characterized in 1968 (1), is believed to be a member of this family. The clinical expression of the disease is surprisingly variable.