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Purpose To determine the various haptoglobin genotypes and their influence on the clinico-laboratory manifestations among young Nigerian sickle cell anemia (SCA) patients. Patients and methods A total of 101 SCA patients and 64 controls were studied. SCA was diagnosed by polymerase chain reaction (PCR). Haptoglobin genotype was determined by PCR followed by agarose gel electrophoresis. The patients' laboratory and clinical parameters were differentiated by haptoglobin genotypes. Results The Hp1 and Hp2 alleles frequencies were 0.62 and 0.38 in the patients and 0.73 and 0.27 in the controls, respectively, and these did not differ significantly (p>0.05). The haptoglobin genotype distribution among the patients and controls were Hp1-1, 43 (42.6%); Hp2-1, 40 (39.6%); Hp2-2, 18 (17.8%) and Hp1-1, 35 (54.7%); Hp2-1, 24 (37.5%); Hp2-2, 5 (7.8%), respectively, with no difference between the two groups (P>0.05). No significant difference was found in the clinical events and laboratory parameters of the patients when partitioned according to the various haptoglobin genotypes (P> 0.05). Conclusion This study found that haptoglobin gene polymorphism does not have a significant influence on the clinico-laboratory manifestations among SCA patients.

Hb Bristol-Alesha [HBB: c.202G>A; β 67 Val>Met] is a rare structural variant of hemoglobin (Hb) resulting from a GTG>ATG substitution at codon 67 of the β-globin gene that leads to the replacement of valine by methionine in the corresponding position of the β-globin chain. The methionine residue is subsequently modified to aspartic acid [β67(E11)Val-Met→Asp], possibly by autoxidation mechanisms. This substitution prevents normal non-polar binding of Val67 to the heme group, resulting in molecular instability and severe hemolysis. We identified Hb Bristol-Alesha (in the heterozygous state), as the cause of severe congenital hemolytic anemia in an 11-month-old girl of mixed (native Indian and European) ethnic origin from the Midwestern region of Brazil, whose parents were clinically and hematologically normal. The mutation on the β-globin gene was found to have been coinherited with the α212 patchwork allele.

Three novel α-globin variants were found during a screening program for hemoglobinopathies in blood donors at the UNICAMP Hematology and Hemotherapy Center, Campinas, State of Sao Paulo, Southeastern Brazil. They were named for the town of origin of the carrier as Hb Itapira [α30(B11)Glu→Val], Hb Bom Jesus da Lapa [α30(B11)Glu→Ala] and Hb Boa Esperanca [α16(A14)Lys→Thr]. Hb Itapira, like Hb Bom Jesus da Lapa, shows an electrophoretic mobility similar to that of Hb S [β6(A3)Glu→Val, GAG→GTG] at alkaline pH; it is associated with a triplicate α-globin allele (αααanti 3.7) and corresponds to only 5.5% of the total hemoglobin (Hb). Hb Boa Esperanca, found in two different individuals, moves faster than Hb A and exhibits an abnormal functional performance.

Point mutations affecting codons 12, 13 (exon 1) and 61 (exon 2) of the N-RAS gene and codons 12 and 13 (exon 1) of the K-RAS gene are identified in approximately 30.0% and 10.0%, respectively, of multiple myeloma (MM) patients living in the northern hemisphere. To date, there are no reports about the prevalence of RAS gene mutations in MM Brazilian patients, and this comprised the aim of the present study. DNA from bone marrow aspirates of 252 patients with MM (139 males and 113 females; aged 59.33 +/- 11.95 years) were investigated for whole exons 1 and 2 of the N-RAS gene and whole exon 1 of the K-RAS gene by direct sequencing of DNA amplified in vitro by the polymerase chain reaction. Fifty-three out of 252 (21.03%) MM patients presented RAS mutations. Heterozygous mutations at codons 4, 10 (exon 1), 61 and 65 (exon 2) of the N-RAS gene were identified in seven out of 252 (2.78%) patients. K-RAS heterozygous mutations at codons 7, 12, 13 (exon 1) were seen in 46 out of 252 (18.25%) patients. To the best of our knowledge, the mutation at codon 7 of K-RAS gene is reported for the first time in MM. Taken together, these results suggest that Brazilian MM patients are characterized by: (i) a low prevalence of RAS mutation and (ii) RAS mutations located at distinct regions of the critical codons of the N-RAS and K-RAS genes.

Analysis of DNA polymorphic sites is an important tool for the detection of gene flow in human evolutionary studies and to study the genetic background for gene mutations. The β-globin locus contains several single-base restriction fragment length polymorphism (RFLP) sites throughout chromosome 11. In addition to these polymorphic sequence repeats, others are being studied in order to expand our knowledge concerning the role between haplotype-genotype and phenotype associations. Far downstream of the expressed β-globin genes, there is a hypersensitive site (HS) whose function remains obscure. We sequenced this region in 27 thalassemia patients and found a new pattern in the micro-satellite-like AT-rich region of this site: a new TAA insertion in addition to the one previously described in sickle cell patients with a concomitant polymorphism (G→A). This new variation was found to be linked to the IVS-I-6 (T→C) mutation. This polymorphism may be useful for studies concerning genotype and phenotype associations.

A novel hemoglobin (Hb) variant was found during a screening program for hemoglobinopathies in blood donors at the Hematology Center of the State University of Campinas, Campinas, Brazil. The carri...