Premium
Asymptomatic homozygous deletional β 0 ‐thalassemia in an African individual
Author(s) -
Faustino Paula,
Reis Ana Batalha,
Feliciano Helena,
Ferrão Lénia,
Pereira Patrícia,
Picanço Isabel,
Miranda Armandina,
Seixas Teresa,
Romão Luísa,
Júnior Esmeraldina Correia,
Lavinha João
Publication year - 2002
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.10118
Subject(s) - compound heterozygosity , thalassemia , haplotype , genotype , hemoglobinopathy , genetics , heterozygote advantage , hemolytic anemia , allele , asymptomatic , biology , fetal hemoglobin , phenotype , globin , medicine , immunology , gene , fetus , pregnancy
Homozygosity or compound heterozygosity for β 0 ‐thalassemia mutations most commonly results in a transfusion‐dependent thalassemia major phenotype. In this report, we describe a 55‐year‐old male, from Guinea‐Bissau, that had been asymptomatic and never transfused until being admitted to hospital with anemia, fever, splenomegaly, and asthenia. Following hospital admission, HIV‐2 and Mycobacterium tuberculosis infections were diagnosed, and biochemical and molecular studies revealed homozygosity for β 0 ‐thalassemia. At the molecular level, this is the first description of homozygosity for the β 0 ‐Black 1,393‐bp deletion. In this case, the complete absence of β‐globin gene expression seems to be compensated by an unusually high fetal globin gene expression (Hb F 96%). β‐Globin haplotyping results were compatible with the propositus being homozygous for the Black 2 haplotype and for the absence of the Xmn I polymorphism at −158 of G γ‐globin gene (−/−). Co‐inheritance of genetic factors usually associated with high Hb F levels was not detected. Otherwise, the propositus is a heterozygote for the α‐globin gene 3.7‐kb deletion that is a beneficial modulating factor but not sufficient to explain this extremely mild phenotype. This unusual genotype/phenotype association is discussed in terms of the mechanisms underlying hemoglobin switching during development. Am. J. Hematol. 70:232–236, 2002. © 2002 Wiley‐Liss, Inc.