Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Molecular cloning and sequence analysis of a nondeletion form of Sicilian beta o hereditary persistence of fetal hemoglobinemia (HPFH) (mutation in IVS2 nt1 position) homozygous for haplotype III revealed the presence of four sequence variations: C----T at -158 5' to G gamma, T----C at +2285, C----A at +2476, and A----G at +2676, all 3' to A gamma. The latter three variations in the putative A gamma enhancer are identical to those observed in the case of Seattle HPFH. However, a severe beta o-thalassemia case from Algeria (mutation in IVS1 nt1 position), also homozygous for haplotype III, revealed the same nucleotide variation, albeit an inefficient HbF production. We conclude that the variations in the A gamma enhancer element do not play a role in the regulation of HbF production. To assess both the linkage of these sites with the beta-cluster haplotype and the extent of the polymorphism, we examined several black and Mediterranean chromosomes, by PCR amplification followed by both EspI digestion and oligonucleotide hybridization. Our data indicate that these sequence variations in the enhancer element are absent in Mediterranean haplotypes I, V, and VII but are consistently associated with Mediterranean haplotypes II, III, and IX, as well as with the black beta c-associated haplotype. The common feature of all the latter haplotypes is the presence of a polymorphic PvuII site between A gamma and psi beta, which is thus in linkage disequilibrium with the variations in the A gamma enhancer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nucleotide variations in the 3' A gamma enhancer region are linked to beta-gene cluster haplotypes and are unrelated to fetal hemoglobin expression. 247 42

beta-Thalassemia is one of the most common genetic diseases in Taiwan. The most common mutations of beta-globin are point mutations, and six mutations account for over 90% of cases. Less than 5% of the cases with beta-globin gene deletion result in beta-thalassemia minor. The mutational type of the deletion is not clear in Taiwanese. We used polymerase chain reaction (PCR)-based methods to detect the breakpoint junctions of different deletional types of beta-thalassemia. In total, six cases of clinically suspected deletional type of beta-thalassemia were studied. The results showed that there were three types of deletions in these cases: two cases each for hereditary persistent fetal hemoglobinemia (HPFH) of the Southeast Asian (SEA) type, HPFH of the Yunnanese type, and gamma(G)+(gamma(A)deltabeta)(0)deletions, respectively. The clinical features of these deletional mutations are milder than the beta(o) types of the point mutation. The patients with compound heterozygous mutations of the point mutation and the deletional mutation are always transfusion independent.
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PMID:Molecular characterization of deletional forms of beta-thalassemia in Taiwan. 1257 62