High prevalence of alpha-thalassemia among individuals with microcytosis and hypochromia without anemia

Autor(es)

E. Borges ^[1] ; M.R.S.C. Wenning ^[2] ; E.M. Kimura ^[3] ; S.A. Gervásio ^[4] ; F.F. Costa ^[5] ; M.F. Sonati ^[6]

Afiliação do(s) autor(es)

^[1] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Patologia Clínica

^[2] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Patologia Clínica

^[3] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Patologia Clínica

^[4] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Patologia Clínica

^[5] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Clínica Médica - Brasil

^[6] Universidade Estadual de Campinas. Faculdade de Ciências Médicas. Departamento de Patologia Clínica

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 34, n. 6, p. 759-762, 2001-06-00.

Resumo

In order to determine the contribution of alpha-thalassemia to microcytosis and hypochromia, 339 adult outpatients seen at Unicamp University Hospital (with the exception of the Clinical Hematology outpatient clinics), who showed normal hemoglobin (Hb) levels and reduced mean corpuscular volume and mean corpuscular hemoglobin, were analyzed. Ninety-eight were Blacks (28.9%) and 241 were Caucasians (71.1%). In all cases, Hb A2 and F levels were either normal or low. The most common deletional and nondeletional forms of alpha-thalassemia [-alpha3.7, -alpha4.2, --MED, -(alpha)20.5, alphaHphIalpha, alphaNcoIalpha, <FONT FACE="Symbol">aa</FONT>NcoI and alphaTSAUDI] were investigated by PCR and restriction enzyme analyses. A total of 169 individuals (49.9%) presented alpha-thalassemia: 145 (42.8%) were heterozygous for the -alpha3.7 deletion (-alpha3.7/<FONT FACE="Symbol">aa</FONT>) and 18 (5.3%) homozygous (-alpha3.7/-alpha3.7), 5 (1.5%) were heterozygous for the nondeletional form alphaHphIalpha (alphaHphIalpha/<FONT FACE="Symbol">aa</FONT>), and 1 (0.3%) was a --MED carrier (--MED/<FONT FACE="Symbol">aa</FONT>). Among the Blacks, 56 (57.1%) showed the -alpha3.7/<FONT FACE="Symbol">aa</FONT> genotype, whereas 12 (12.2%) were -alpha3.7/-alpha3.7 and 1 (1.0%) was an alphaHphIalpha carrier; among the Caucasians, 89 (36.9%) were -alpha3.7/<FONT FACE="Symbol">aa</FONT>, 6 (2.5%) had the -alpha3.7/-alpha3.7 genotype, 4 (1.7%) presented the nondeletional form (alphaHphIalpha/<FONT FACE="Symbol">aa</FONT>), and 1 (0.4%) was a --MED carrier. These results demonstrate that alpha-thalassemia, mainly through the -alpha3.7 deletion, is an important cause of microcytosis and hypochromia in individuals without anemia. These data are of clinical relevance since these hematological alterations are often interpreted as indicators of iron deficiency. (AU)

• Processo FAPESP: 97/11725-1 - Genética molecular das alterações hereditárias da hemoglobina e estudo funcional dos genes globina gama
• Beneficiário: Fernando Ferreira Costa
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 98/14532-2 - Contribuicao da talassemia alfa na microcitose e hipocromia da populacao brasileira.
• Beneficiário: Maria de Fatima Sonati
• Modalidade de apoio: Auxílio à Pesquisa - Regular