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Molecular characterization of sickle cell anemia in the Northern Brazilian state of Pará

Authors

  • Greice De Lemos Cardoso,

    1. Laboratory of Human and Medical Genetics, Institute for Biological Sciences, Federal University of Pará, 66075-110 Belém, Pará, Brazil
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  • João Farias Guerreiro

    Corresponding author
    1. Laboratory of Human and Medical Genetics, Institute for Biological Sciences, Federal University of Pará, 66075-110 Belém, Pará, Brazil
    • Laboratory of Human and Medical Genetics, Institute for Biological Sciences, Federal University of Pará, 66075-110 Belém, Pará, Brazil
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Abstract

To assess α+-thalassemia deletion alleles, β-thalassemia mutations and haplotypes linked to the HBB*S cluster in a sample of 130 unrelated sickle cell anemia (SCA) patients (55% female) from Belém, Pará State, for their possible effects on the patients' survival. -α3.7, -α42, -α20.5, and –MED α+-thalassemia deletion alleles were investigated using multiplex gap-PCR method. Characterization of β-thalassemia mutations was made by direct genomic sequencing of the β-globin gene amplified through polymerase chain reaction (PCR). Haplotypes were determined by analysis of six polymorphic restriction sites [(1) XmnI-5′γG, (2) HindIII-γG, (3) HindIII-γA, (4) HincII-ψβ, (5) HincII-3′ψβ, and (6) HinfI-5′β] followed by restriction digestion and agarose gel electrophoresis. Twenty-one patients (16%) presented -α3.7 thalassemia. Sixteen of those (76%) were heterozygous (-α3.7/αα) and 5 (24%) were homozygous (-α3.7/-α3.7). -α4.2, -α20.5 and –MED deletions were not found. Nine cases of sickle cell-β thalassemia were found and four different β-thal mutations were identified: β+ −88 (C>T), 3.8%; β+ codon 24 (T > A), 1.5%; β+ IVSI-110 (G > A), 0.7% and β (IVSI-1 (G > A), 0.7%. No differences according to age were observed in -α3.7 deletion, β-thalassemia and HHB*S haplotypes distribution. Our results suggest that although α- and β-thalassemia and βS haplotypes may have modulating effect on clinical expression and hematological parameters of SCA, these genetic variables probably have little influence on the subjects' survival. Am. J. Hum. Biol. 22:573–577, 2010. © 2010 Wiley-Liss, Inc.

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