Hb Florida: a novel elongated C-terminal beta-globin variant causing dominant beta-thalassemia phenotype

We report here a new frameshift mutation in exon 3 of the beta-globin gene, a single nucleotide deletion (-C) in between codons 140/141 (GCC/CTG-->GCC/TG), found in an 8-year-old Argentinean girl with clinical picture of thalassemia intermedia. It leads to a beta-chain that is elongated to 156 amino acids [(141)Trp-Pro-Thr-Ser-Ile-Thr-Lys-Leu-Ala-Phe-Leu-Leu-Ser-Asn-Phe-(156)Tyr-COOH]. The resulting hemoglobin, which we named Hb Florida, was not detected in peripheral blood; however, erythroid hyperplasia and dyserythropoiesis with large inclusion bodies on methyl violet staining were observed in bone marrow, suggesting that this is a hyperunstable variant producing a dominant beta-thalassemia phenotype, since the other beta-allele was completely normal.

Reticulocyte evaluation in alpha(+)-thalassemia

Although it is almost certain that alpha(+)-thalassemia protects against malaria, the mechanisms for that are still unknown. It has been suggested that an increased number of young circulating red blood cells in alpha(+)-thalassemic children, as a result of some degree of ineffective erythropoiesis, could be related to the high frequencies of the alpha(+)-thalassemic allele in malaria endemic areas. Reticulocyte evaluation in this condition, however, has been poorly performed so far. Our objective was to determine the reticulocyte number and maturation degree, in addition to the soluble transferrin receptor and serum erythropoietin levels, in alpha(+)-thalassemia heterozygotes, comparing them with normal alpha-genotype controls. One hundred twenty-one alpha(+)-thalassemia carriers (-alpha(3.7)/alphaalpha) and 249 controls (alphaalpha/alphaalpha), all of them with normal serum ferritin levels, were subclassified according to age (1-5, 6-10, 11-15, 16-20, and over 20 years old). Reticulocyte analyzes were carried out by flow cytometry and sTfR and s-Epo levels determined by immunonephelometry and chemiluminescence, respectively. The comparisons did not show any significant difference between thalassemics and controls regarding the reticulocyte parameters [percentages and absolute values, P = 0.2643 and 0.5421; high, medium, and low maturation degree, P = 0.2579, 0.2196, and 0.4192; RET maturity index (RMI), P = 0.2471, respectively], as well as the s-Epo levels (P = 0.5711). The sTfR concentrations were higher in the thalassemic group (P = 0.0001), but statistical significance was due only to the 1-5 and over 20 subgroups (P = 0.0082 and 0.0436, respectively). The results found here are compatible with a compensated erythropoiesis and do not confirm the hypothesis mentioned above.

Rhnull syndrome: identification of a novel mutation in RHce

BACKGROUND

The deficiency of Rh proteins on red blood cells (RBCs) from individuals of the Rh(null) amorph type are the result of homozygosity for a silent RHCE in cis with a deleted RHD. A novel mutation in RHce was identified in two Caucasian Brazilian girls with the amorph type of Rh(null) who were born to parents who were first cousins.

STUDY DESIGN AND METHODS

RBCs from the Rh(null) sisters and from family members were analyzed by serology and flow cytometry with specific antibodies. Genomic DNA and transcripts were tested by polymerase chain reaction and sequence analysis.

RESULTS

Rh(null) RBCs were nonreactive with anti-Rh and anti-LW. Molecular analyses showed a deletion of RHD and of one nucleotide (960/963; GGGG-->GGG) in exon 7 of the RHce. This deletion introduced a frameshift after Gly321, a new C-terminal sequence, and a premature stop codon, resulting in a shorter predicted protein with 357 amino acids.

CONCLUSION

The detection of a unique RHce transcript indicated that the two sisters were homozygous, whereas the other family members were heterozygous for the mutation. A novel mutation resulting in the amorph Rh(null) with loss of Rh antigen expression is described.

Increasing seroprevalence of Human herpesvirus 8 (HHV-8) with age confirms HHV-8 endemicity in Amazon Amerindians from Brazil

Human herpesvirus 8 (HHV-8) seroprevalences were determined in two isolated Amazon Amerindian tribes, according to age, gender and familial aggregation. Plasma and serum samples obtained from 982 Amazon Amerindians (664 Tiriyó and 318 Waiampi) were tested for antibodies against lytic and latent HHV-8 antigens by using ‘in-house’ immunofluorescence assays. Overall, HHV-8 seroprevalence was 56·8 % (57·4 % in the Tiriyó tribe and 55·7 % in the Waiampi tribe). Seroprevalence was independent of gender and increased linearly with age: it was 35·0 % among children aged 2–9 years, 51·4 % in adolescents (10–19 years), 72·9 % in adults and 82·3 % in adults aged >50 years. Interestingly, 44·4 % of children under 2 years of age were HHV-8-seropositive. No significant differences in seroprevalence between tribes and age groups were detected. It is concluded that HHV-8 is hyperendemic in Brazilian Amazon Amerindians, with vertical and horizontal transmission during childhood, familial transmission and sexual contact in adulthood contributing to this high prevalence in these isolated populations.

Hemochromatosis (HFE) gene mutations in Brazilian chronic hemodialysis patients

Patients with chronic renal insufficiency (CRI) have reduced hemoglobin levels, mostly as a result of decreased kidney production of erythropoietin, but the relation between renal insufficiency and the magnitude of hemoglobin reduction has not been well defined. Hereditary hemochromatosis is an inherited disorder of iron metabolism. The importance of the association of hemochromatosis with treatment for anemia among patients with CRI has not been well described. We analyzed the frequency of the C282Y and H63D mutations in the HFE gene in 201 Brazilian individuals with CRI undergoing hemodialysis. The analysis of the effects of HFE mutations on iron metabolism and anemia with biochemical parameters was possible in 118 patients of this study (hemoglobin, hematocrit, ferritin levels, transferrin saturation, and serum iron). A C282Y heterozygous mutation was found in 7/201 (3.4%) and H63D homozygous and heterozygous mutation were found in 2/201 (1.0%) and 46/201 (22.9%), respectively. The allelic frequencies of the HFE mutations (0.017 for C282Y mutation and 0.124 for H63D mutation) did not differ between patients with CRI and healthy controls. Regarding the biochemical parameters, no differences were observed between HFE heterozygous and mutation-negative patients, although ferritin levels were not higher among patients with the H63D mutation (P = 0.08). From what we observed in our study, C282Y/H63D HFE gene mutations are not related to degrees of anemia or iron stores in CRI patients receiving intravenous iron supplementation (P > 0.10). Nevertheless, the present data suggest that the H63D mutation may have an important function as a modulating factor of iron overload in these patients.

A novel FY allele in Brazilians

The GATA box single nucleotide polymorphism (SNP) at position -33 (T>C) in Blacks silences the expression of FY*B in erythrocytes, and the substitution 265 C>T, together with 298 G>A, weakens the Fy(b) antigen (Fy(x)). Individuals with these phenotypes/genotypes who receive Fy(b+) blood are unlikely to be alloimmunized to Fy(b) because, in the presence of 265 T, the Fy(b) antigen is expressed, and in the case of -33 C, other tissues express Duffy protein and probably the Fy(b) antigen. We studied samples from 361 blood donors (182 of African ancestry and 179 of Caucasian ancestry) by haemagglutination and polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). Forty Caucasian and 130 donors of African ancestry were serologically Fy(b-); among these, the majority of the donors of African ancestry had FY*B with the GATA SNP, while the majority of Caucasians typing Fy(b-) had FY*B with 265 T/298 A SNPs. Six of the Fy(b-) donors (three Africans and three Caucasians) had both GATA and 265/298 SNPs, and six donors of Caucasian ancestry apparently had a GATA SNP. Samples from two donors - one African and one Caucasian with an unusual MspA1I-RFLP pattern - were sequenced and found to have a novel SNP (145 G>T) co-existent with 265 C>T and 298 G>A SNPs. These findings highlight the importance of establishing the incidence and nature of molecular events that impact on Duffy expression in different populations.

High frequency of partial DIIIa and DAR alleles found in sickle cell disease patients suggests increased risk of alloimmunization to RhD

We have set out to determine the frequency of DIIIa and DAR alleles among sickle cell disease (SCD) patients. These D variants permit the unexpected development of antibodies to RhD among individuals who are otherwise classified as RhD+. DNA samples from 130 SCD patients were tested for 455A>C (specific for DIIIa), 602C>G, 667T>G (common for both DIIIa and DAR) and 1025T>C (specific for DAR) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence analysis. The PCR-RFLP showed that 12 (9.2%) of the SCD patients were carrying DIIIa and DAR alleles. Genomic DNA analysis performed by sequence showed that three samples were heterozygous DIIIa (2.3%), seven heterozygous DAR (4.6%) and two (1.5%) samples carried a partial D with four mutations: 455A>C (heterozygous), 602C>G and 667T>G (homozygous) and 1025T>C (heterozygous), indicating compound heterozygosity for one DIIIa allele and one DAR allele. The predicted phenotypes of eight (6.2%) SCD patients were DIIIa, DAR and DIIIa/DAR. Three patients were anti-D immunized (DAR, n = 1; DIIIa/DAR, n = 2). These findings suggest that SCD patients who are candidates for chronic transfusion may benefit from genotyping for DIIIa and DAR to prevent alloimmunization.

Association of ABO gene mutations resulting in a rare B subgroup

BACKGROUND AND OBJECTIVES

B subgroups are rare and the genetic analysis reported to date has been limited.

MATERIALS AND METHODS

Serological and molecular investigations were performed in blood from a B-subgroup donor.

RESULTS

Red cells did not react with anti-B and anti-AB reagents. However, cells absorbed anti-B. Red cells presented positive reactions with anti-H, and saliva secreted H substance. The molecular study demonstrated a B allele with the substitutions 467C>T, 646T>A, 681G>A, 771C>T, 796C>A, 803G>C, 829G>A and an O allele with the sequence of O02.

CONCLUSIONS

It is probable that the presence in exon 7 of some of the O02 substitutions could have weakened the enzymatic activity of the encoded B transferase.

Polymorphism of the human platelet antigen-5 system is a risk factor for occlusive vascular complications in patients with sickle cell anemia

BACKGROUND

Polymorphisms of platelet membrane glycoproteins such as human platelet antigen (HPA)-1b, HPA-2b, the -5T/C Kozak sequence and C807T have been described as risk factors for vascular disease. Vaso-occlusion episodes are a common feature of sickle cell anaemia (SCA), leading to complications such as stroke, acute chest syndrome, avascular head femur necrosis and priapism. Complex interactions are involved in vaso-occlusion, and activated platelets may play an important role. These data raised the question of whether platelet polymorphisms could be implicated in occlusive vascular complications (OVC) of SCA.

MATERIALS AND METHODS

In this study, 97 patients with SCA were analysed in two groups: 34 patients presenting with OVC (SCA-VC) and 63 without these complications (SCA-N). The distribution of the HPA-1, -2 and -5 systems, as well as C807T dimorphism and -5T/C Kozak sequence alleles, was evaluated using DNA-based methods.

RESULTS

Patients of the SCA-VC group showed a higher frequency of the HPA-5b allele (0.324) compared with those of the SCA-N group (0.111) (chi2 = 13.19, P = 0.0002). None of the other polymorphisms, isolated or associated as haplotypes, demonstrated any correlation with the development of OVC in these patients.

CONCLUSIONS

The findings of this study suggest that the HPA-5b allele is a genetic risk factor for the development of OVC in patients with SCA. This allele could be explored as a target for the development of new therapeutic approaches.

Weakened expression of 'e' owing to concomitant occurrence of Cys16 and Val245 (VS antigen)

BACKGROUND AND OBJECTIVES

The 48 G>C transversion in exon 1 of the RHCE gene leads to Trp16Cys, usually present in the conventional RHCE Ce, while Trp16 is associated with RHCE ce. The presence of Cys16 in RHCE ce is associated with the R(0) (Dce) haplotype in Africans, leading to a weak 'e' antigen expression on red blood cells (RBCs). VS is a common red cell antigen in individuals of African descent and results from a single point mutation in exon 5 of the RHCE (733C>G), leading to Leu245Val substitution; VS positivity is also associated with weak expression of 'e'. This study investigated the association of Cys16 and/or VS with the RHCE ce alleles in a cohort of sickle cell disease (SCD) patients phenotyped as R(0)r or R(0)R(0) and rr.

MATERIALS AND METHODS

DNA samples from 58 SCD patients were tested for the 48 G>C transversion, encoding Cys16, by allele-specific polymerase chain reaction (PCR). We also amplified exon 5 of the RHCE by PCR and subjected the amplified product to restriction fragment length polymorphism analysis, using BfaI, in order to determine the VS status. Further cDNA analysis was performed on three samples to verify whether the mutations were located on the same or on different alleles.

RESULTS

Fifty-six of the 58 SCD patients studied (97%) were heterozygous for 48G/48C (Cys16). Of these, 18 (32%) were also heterozygous for 733C/G (245Val). All of these 18 samples showed weak 'e' expression on RBCs when tested with at least one monoclonal antibody to e antigen. cDNA sequencing of three of 18 patient samples showed that the genes encoding Cys16 and Val245 (VS) were on different alleles.

CONCLUSIONS

We found a high incidence of Cys16 associated with the RHCE ce in our SCD cohort. A high percentage of these patients were also found to be heterozygous for VS. cDNA analysis showed that, in at least three samples, the two mutations were on different alleles, with consequent weakening of expression of the e antigen on RBCs.

Analysis of the mechanism of action of the Brazilian type (A γ −195 C → G) of hereditary persistence of fetal hemoglobin

We report an in vitro expression study of the Agamma-globin gene promoter containing the Agamma-195 C --> G mutation that causes the Brazilian type of hereditary persistence of fetal hemoglobin (HPFH). To demonstrate that this mutation results in increased promoter strength, we evaluated the mutant promoter linked to the hypersensitive site-2 of the locus control region with the luciferase reporter gene system and examined protein interactions by eletrophoretic mobility shift assay. The transient expression was studied in three cell lines: K562, HEL and 293, and indicated increased promoter activity of the promoter containing the Brazilian mutation in all cell lines. The protein-DNA interaction showed that, in contrast to the Agamma-198 T --> C mutation which has increased affinity for the Sp1 protein and creates a motif that behaves like a novel CACCC box in the gamma promoter, the Brazilian HPFH mutation decreases the affinity at the Sp1 protein and does not act as a CACCC motif. These results suggest that this mutation may act to increase the Agamma-globin chain production. In addition, the mechanism by which this increased production occurs is different to that of the -198 mutation. Other proteins may be involved in the overexpression of the gamma-globin chain and/or may be dependent upon the DNA structure.

Screening for mutations in human alpha-globin genes by nonradioactive single-strand conformation polymorphism

Point mutations and small insertions or deletions in the human alpha-globin genes may produce alpha-chain structural variants and alpha-thalassemia. Mutations can be detected either by direct DNA sequencing or by screening methods, which select the mutated exon for sequencing. Although small (about 1 kb, 3 exons and 2 introns), the alpha-globin genes are duplicate (alpha2 and alpha1) and highly G-C rich, which makes them difficult to denature, reducing sequencing efficiency and causing frequent artifacts. We modified some conditions for PCR and electrophoresis in order to detect mutations in these genes employing nonradioactive single-strand conformation polymorphism (SSCP). Primers previously described by other authors for radioactive SSCP and phast-SSCP plus denaturing gradient gel electrophoresis were here combined and the resultant fragments (6 new besides 6 original per alpha-gene) submitted to silver staining SSCP. Nine structural and one thalassemic mutations were tested, under different conditions including two electrophoretic apparatus (PhastSystem and GenePhor, Amersham Biosciences), different polyacrylamide gel concentrations, run temperatures and denaturing agents, and entire and restriction enzyme cut fragments. One hundred percent of sensitivity was achieved with four of the new fragments formed, using the PhastSystem and 20% gels at 15 degree C, without the need of restriction enzymes. This nonradioactive PCR-SSCP approach showed to be simple, rapid and sensitive, reducing the costs involved in frequent sequencing repetitions and increasing the reliability of the results. It can be especially useful for laboratories which do not have an automated sequencer.

Elastic properties of stored red blood cells from sickle trait donor units

BACKGROUND AND OBJECTIVES

Red blood cells (RBCs) from patients with sickle cell disease present reduced deformability. The aim of this study was to analyse the elasticity of stored RBCs from patients with the sickle cell trait (AS).

MATERIALS AND METHODS

The cell elasticity was studied, using laser optical tweezers, on storage days 1, 14, 21, 28 and 35.

RESULTS

The elasticity of RBC from AS units stored for 1, 14 and 21 days was significantly greater compared with that of control RBC cells stored for the same time-period. More than 30% of the cells from AS units stored for 28 or 35 days were very rigid and escaped from the optical trap.

CONCLUSIONS

RBCs became rigid during storage, suggesting that haemoglobin S might compromise the cell elasticity.

A possible role of the P53 gene deletion as a prognostic factor in multiple myeloma

The role of P53 gene abnormalities in the pathogenesis of multiple myeloma (MM) and their potential use as prognostic indicators remain uncertain. To further define this question, we studied genomic DNA from 50 MM and one plasma cell leukemia patients by polymerase chain reaction single-strand conformation polymorphism and sequencing, and fluorescence in situ hybridization in order to detect P53 mutation and deletion, respectively. Kaplan-Meier survival curves and the log-rank test were used to analyze the survival data. No P53 mutation was detected in our patients. In contrast, P53 deletion, predominantly monoallelic, was detected in 8 of 51 (15.7%) patients. Similar frequencies of P53 deletion were observed in patients stratified by age ( P=0.71), gender ( P=0.44), status, and stage of the disease ( P=0.70 and P=0.23, respectively). However, patients with P53 deletion had significantly shorter median overall survival compared with those without a deletion (7.4 vs 139.0 months, P<0.0001). On univariate regression analysis, P53 deletion was a parameter for predicting shortened survival ( P=0.02). We concluded that P53 mutation may be seen as a prognostic indicator of limited value in MM. In contrast, P53 deletion may be seen as a prognostic indicator of poor outcome. However, as the cohort of patients is rather limited for a prognostic analysis, these results should be confirmed by further studies with larger sized samples.

Identification, structural characterization, and tissue distribution of Tsg-5: a new TNF-stimulated gene

Using DDRT-PCR, we compared the mRNA content of untreated and TNF-treated mouse embryonic fibroblasts (MEFs). Among differentially represented fragments, we identified and cloned a novel TNF-stimulated gene named Tsg-5. This gene, mapped to mouse chromosome 14, has three exons that can be alternatively spliced giving rise to two mRNA species, one spanning three exons and another that skips the second exon. Analysis of full-length Tsg-5 cDNA revealed a potential start codon within exon 2 encoding an ORF of 40 amino-acids. No homology with known mouse or human sequences, neither at the nucleotide nor at the amino-acid level could be found in public databases. In MEFs, Tsg-5 is induced by tumor necrosis factor-alpha (TNF) and IL-1 beta, albeit with distinct kinetics. TNF-induced Tsg-5 expression is NF-kappa B-dependent as it was inhibited by MG132, lactacystin, Bay 11-7083, and Bay 11-7085. Analysis of Tsg-5 expression in vivo revealed that the gene and its encoded polypeptide are constitutively expressed in the thymus and ovary, whereas, in LPS-treated mice, Tsg-5 mRNA can be detected in the spleen, lung, and brain. Our data suggest that Tsg-5 encodes a new, rare transcript, with a very tight regulation of expression and differential splicing.

Thalassemia intermedia as a result of heterozygosis for beta 0 -thalassemia and alpha alpha alpha anti-3,7 genotype in a Brazilian patient

We report a case in which the interaction of heterozygosis for both the 0-IVS-II-1 (G->A) mutation and the alpha alpha alpha anti-3,7 allele was the probable cause for the clinical occurrence of thalassemia intermedia. The propositus, a 6-year-old Caucasian Brazilian boy of Portuguese descent, showed a moderately severe chronic anemia in spite of having the -thalassemia trait. Investigation of the alpha-globin gene status revealed heterozygosis for alpha-gene triplication (alpha alpha alpha / alpha alpha). The patient's father, also presenting mild microcytic and hypochromic anemia, had the same alpha and genotypes as his son, while the mother, not related to the father and hematologically normal, was also a carrier of the alpha alpha alpha anti-3,7 allele. The present case emphasizes the need for considering the possibility of alpha-gene triplication in -thalassemia heterozygotes who display an unexpected severe phenotype. The -thalassemia mutation found here is being described for the first time in Brazil.

Optical tweezers for measuring red blood cell elasticity: application to the study of drug response in sickle cell disease

The deformability of erythrocytes is a critical determinant of blood flow in microcirculation. By capturing red blood cells (RBC) with optical tweezers and dragging them through a viscous fluid we were able to measure their overall elasticity. We measured, and compared, the RBC deformability of 15 homozygous patients (HbSS) including five patients taking hydroxyurea (HU) for at least 6 months (HbSS/HU), 10 subjects with sickle cell trait (HbAS) and 35 normal controls. Our results showed that the RBC deformability was significantly lower in haemoglobin S (HbS) subjects (HbSS and HbAS), except for HbSS/HU cells, whose deformability was similar to the normal controls. Our data showed that the laser optical tweezers technique is able to detect differences in HbS RBC from subjects taking HU, and to differentiate RBC from normal controls and HbAS, indicating that this is a very sensitive method and can be applied for detection of drug-response in sickle cell disease.

ABO blood group in Amerindians from Brazilian Amazon

BACKGROUND

The Parakanã is a group of Indians with cultural similarities to the extinct Tupi group. They are an isolated native population from East Brazilian Amazon. A number of different O alleles have been found at the blood group ABO locus in populations of several ethnic origins (Caucasians, Blacks, Amerindians).

AIM

The present study describes the ABO blood group polymorphism gene of the Parakanã Indians. The Amerindian group was carefully selected for racial background.

SUBJECT AND METHODS

The blood group polymorphism was analysed in genomic DNA from 62 Parakanã Indians. We determined the 261G deletion, the T646A and C771T mutations described in O(1variant) and the G542A substitution, using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism).

RESULTS

All Amerindians studied were homozygous for the 261G deletion. The frequencies of the T646A and C771T mutations in Parakanãs (0.65) were lower than that observed in Kayapo, Yanomama and Arara Indians (0.91) (chi (2) = 18.24; p-v < 0.001. The G542A substitution in Parakanãs was also lower (0.22) than in other tribes (0.42) (chi(2) = 9.73; p-v = 0.001).

CONCLUSIONS

The different O alleles including the G542A mutation are not distributed homogeneously among all Amazonian Amerindians. Our results are in agreement with other genetic markers studied previously in Parakanã Indians, whose distinct genetic pattern differs from Europeans and even from other Amerindians.

Accuracy of the urinary albumin to creatinine ratio as a predictor of albuminuria in adults with sickle cell disease

AIM

To test the usefulness of a random urine specimen albumin to creatinine ratio (A/C) in predicting 12 hour urinary albumin excretion (12UA) in patients with sickle cell disease.

METHODS

12UA and A/C were measured in nocturnal urine collections and random morning urine samples, respectively, of 72 patients with sickle cell disease.

RESULTS

The correlation of A/C values with 12UA values did not provide support for the use of random urine specimens for predicting urinary albumin excretion (UAE) in these patients. However, values of A/C >/= 0.45 and < 0.45 were indicative of raised and normal UAE, respectively. The sensitivity, specificity, and accuracy of the test were 100.0%, 87.2%, and 91.7%, respectively.

CONCLUSIONS

This method cannot be recommended for predicting 12UA in patients with sickle cell disease, but it is useful for selecting patients who should collect 12 hour urine for the estimation of UAE.

Hemoglobin H disease resulting from the association of the - alpha 3.7 rightward deletion and the (alpha alpha)MM deletion in a Brazilian patient

A patient with Hb H disease resulting from the association of the - alpha 3.7 rightward deletion with the rare (alpha alpha)MM deletion, which removes the entire alpha-major regulatory element (MRE), is reported. This is the first description of an alpha-thalassemic mutation resulting from deletion of the locus-controlling sequences in the South-American population.

Elastic properties of irradiated RBCs measured by optical tweezers

BACKGROUND

Gamma irradiation of RBCs results in the production of reactive oxygen capable of initiating the process of membrane lipid peroxidation and accelerates the leakage of potassium ions from RBCs, resulting in an increase of internal viscosity.

STUDY DESIGN AND METHODS

The elastic properties of irradiated and stored RBC units were studied using laser optical tweezers. The laser trapped the cell and the membrane elasticity was analyzed, measuring the cell deformation in six different drag velocities. Five RBC units were split into two portions. One portion received a gamma irradiation dose of 25 Gy, and the second one was used as a control and was not irradiated. All units were stored (4 degrees C), and the elasticity was examined on Days 1, 14, 21, and 28.

RESULTS

Elastic properties (mu) from irradiated RBCs stored for 21 and 28 days were significantly affected compared with control cells (21 days: control, 0.3 +/- 0.03 x 10(-3); irradiated, 3.5 +/- 1.3 x 10(-3) dyn/cm; p < 0.001; and 28 days: control, 0.5 +/- 0.09 x 10(-3); irradiated, 14 +/- 3.2 x 10(-3) dyn/cm; p < 0.001).

CONCLUSION

The sensitivity of the laser optical tweezers method showed that there is no significant change in elasticity over time for up to 14 days of storage, regardless of whether the unit was irradiated or not. However, beyond 21 days of storage, irradiated units demonstrate decreased elasticity.

Molecular identification of Sicilian (deltabeta) degrees-thalassemia associated with beta-thalassemia and hemoglobin S in Brazil

We describe the clinical and molecular characteristics of two unrelated Brazilian families with an association of the Sicilian form of (deltabeta) degrees -thalassemia with hemoglobin S and beta-thalassemia. Direct sequencing of the beta-globin gene showed only the hemoglobin S mutation in patient 1 and the beta-thalassemia IVS1-110 in patient 2. The other allele was deleted in both patients and PCR of DNA samples of the breakpoint region of both patients showed a band of approximately 1,150 bp, expected to be observed in the DNA of carriers of Sicilian (deltabeta) degrees -thalassemia. The nucleotide sequence of this fragment confirmed the Sicilian deletion. There are few reports concerning the Hb S/(deltabeta) degrees -thalassemia association and patient 2 is the first reported case of Sicilian type of (deltabeta) degrees -thalassemia in association with beta-thalassemia documented at the molecular level.

beta-Spectrin São PauloII, a novel frameshift mutation of the beta-spectrin gene associated with hereditary spherocytosis and instability of the mutant mRNA

Hereditary spherocytosis (HS) is a common inherited anemia characterized by the presence of spherocytic red cells. Defects in several membrane protein genes have been involved in the pathogenesis of HS. beta-Spectrin-related HS seems to be common. We report here a new mutation in the beta-spectrin gene coding region in a patient with hereditary spherocytosis. The patient presented acanthocytosis and spectrin deficiency and, at the DNA level, a novel frameshift mutation leading to HS, i.e., a C deletion at codon 1392 (beta-spectrin São PauloII), exon 20. The mRNA encoding beta-spectrin São PauloII was very unstable and the mutant protein was not detected in the membrane or in other cellular compartments. It is interesting to note that frameshift mutations of the beta-spectrin gene at the 3' end allow the insertion of the mutant protein in the red cell membrane, leading to a defect in the auto-association of the spectrin dimers and consequent elliptocytosis. On the other hand, beta-spectrin São PauloII protein was absent in the red cell membrane, leading to spectrin deficiency, HS and the presence of acanthocytes.