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

Author(s)

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]

Affiliation

^[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

• Document type: Journal article
• Source: Brazilian Journal of Medical and Biological Research; v. 34, n. 6, p. 759-762, 2001-06-00.

Abstract

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)

• FAPESP's process: 97/11725-1 - Molecular genetics of the hereditary alterations of hemoglobin and functional study of the gamma globin genes
• Grantee: Fernando Ferreira Costa
• Support Opportunities: Research Projects - Thematic Grants