CONTEXT AND OBJECTIVE: Acquired fetal hemoglobin (HbF) elevation has been implicated as a prognostic factor in dyserythropoietic disorders. Our objectives were to examine acquired HbF increases in aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) patients, and to evaluate whether there is an association between the presence of XmnI and 5' hypersensitive site locus control region (LCR-HS2) polymorphisms and the HbF levels. DESIGN AND SETTING: Cross-sectional study at the Hematology and Blood Transfusion Service of Universidade Federal de São Paulo - Escola Paulista de Medicina. METHODS: We studied a group of 37 patients with AA and/or PNH. Polymerase chain reaction (PCR) and enzymatic digestion were utilized to analyze XmnI polymorphisms; and PCR, cloning and automated sequencing for the HS2 polymorphisms. RESULTS: The mean HbF level was 2.32%, but there was no significant difference in HbF level between the AA and PNH groups (p = 0.46). HbF levels of less than 1.0% showed a significant correlation with absence of the XmnI (+) polymorphism (p = 0.02). The presence of the XmnI allele was greater in the AA group (p = 0.007). CONCLUSIONS: XmnI polymorphism absence reduction is associated with acquired HbF elevation. Further studies are required to confirm these observations and make treatment, prognosis and survival comparisons.

The various clinical phenotypes in β-thalassemias have stimulated the study of genetic factors that could modify the manifestations of these diseases. We examined 21 patients with β-thalassemia (β-thal) in order to identify some genetic modifying factors: β-thalassemia mutations, HBG2:g.-158C>T polymorphism, α-globin gene deletions and (AT)xNz(AT)y motif within the hypersensitive site 2-locus control region (HS2-LCR). In the 42 alleles analyzed, the most frequent mutations observed were HBB:c.92+6T>C (30.9%), HBB:c.118C>T (16.7%), HBB:c.93-21G>A (11.9%) and HBB:c.92+1G>A (4.8%); this finding is in accordance with previous data of the Brazilian population. The other genetic factors analyzed showed no relation with the severity of the disease. For the first time in Brazil, we report HBB:c.93-2A>G and HBB:c.114G>A mutations on the β-globin gene, both in a heterozygous state. This is also the first study to analyze the HS2-LCR in β-thalassemic individuals in the Brazilian population.

No abstract

Rev. bras. hematol. hemoter. 2007;29(4):344-345.

1653 Background: Sickle cell disease (SCD) is a monogenic disorder with phenotypic heterogeneity, possibly determined by polymorphisms (SNPs) in genes whose products modify the pathophysiology of the disease. Priapism is one of the most common vaso-occlusive complications of SCD, and it occurred in more than 30% of males. The Klotho (KL) gene appears to be associated with vascular function and nitric oxide biology and the presence of SNPs could affect its function. Association between KL and priapism in SCD patients was suggested by Nolan et al. in 2004. However, other authors could not confirm this finding (Elliot et al., 2007). Objective: We decided to evaluate the relevance of SNPs rs2249358, rs211234 and rs9536314 to the occurrence of priapism in patients with SCD followed at Outpatient clinic at Escola Paulista de Medicina/UNIFESP. Methods: Forty male patients with SCD were enrolled, 39 (97.5%) with sickle cell anemia (SS) and one (2.5%) SC hemoglobinopathy. The manifestation of priapism was identified through analyses of medical records. The SNP rs2249358 was identified by PCR followed by restriction with XbaI. The other SNPs, rs211234 and rs9536314, were analyzed by allele specific PCR. Statistical analysis: t test, Chi2 or Fisher. This study was approved by Ethical Committee, and all patients agreed in participate. Results: The median age of the patient was 28.5 years-old (20-68 y.o.). Fourteen out of 40 patients had priapism (35%), each one with SS disease. The group of patients with priapism were older (32.5 y.o., 25–68 y.o.) than the group without this manifestation (27.5 y.o., 20–56 y.o.) (p=0.03). There was no statistical difference in the distribution of the SNPs rs211234 and rs9536314 between the two groups of patients (p=0.51 and p= 0.09, respectively). Regarding the distribution of SNP rs2249358, the group with priapism presented 8 individuals (57.1%) with GG genotype, 5 (35.7%) with AA and 1 (7.17%) with AG, whereas in the group without priapism, the distribution was different: 5 (19.2%) with GG, 7 (26.9%) with AA and 14 (53.8%) with AG genotype (p=0.0212). When we compare the presence of at least one A allele (AA or A-) with the G allele in homozygosis (GG), we observed that the A allele has a protector effect (OR: 0.1786; CI: 0.04232–0.7535) (p=0.031). Conclusions: In a relatively small group of patients with SCD, it was observed a significant proportion of individuals with priapism, which reinforces the importance of this manifestation. We also observed correlation between SNP rs2249358 of KL gene and priapism, as suggested previously. Disclosures: No relevant conflicts of interest to declare.