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PubMed1992

Thalassemia in SouthEast Asia: problems and strategy for prevention and control.

In Southeast Asia alpha-thalassemia, beta-thalassemia, hemoglobin (Hb) E and Hb Constant Spring are prevalent. The gene frequencies of alpha-thalassemia reach 30-40% in Northern Thailand and Laos. beta-Thalassemia gene frequencies vary between 1 and 9%. Hb E is the hallmark of Southeast Asia attaining a frequency of 50-60% at the junction of Thailand, Laos, and Cambodia. Hb Constant Spring gene frequencies vary between 1 and 8%. These abnormal genes in different combinations lead to over 60 different thalassemia syndromes. The four major thalassemic diseases are Hb Bart's hydrops fetalis (homozygous alpha-thalassemia 1), homozygous beta-thalassemia, beta-thalassemia/Hb E and Hb H diseases. The molecular basis of most of these abnormal genes have been recently described. Therefore, it is possible to set a strategy for prevention and control of thalassemia which includes population screening for heterozygotes, genetic counseling and fetal diagnosis with selective abortion of affected pregnancies.

Asia, Southeastern↗
PubMed2002

Spectrum of beta-thalassemia mutations and their association with allelic sequence polymorphisms at the beta-globin gene cluster in an Eastern Indian population.

In this report, the spectrum of beta-thalassemia mutations and genotype-to-phenotype correlations were defined in large number of patients (beta-thalassemia carriers and major) with varying disease severity in an Eastern Indian population mainly from the state of West Bengal. The five most common beta-thalassemia mutations were detected, which included IVS1-5 (G-->C), codon 15 (G-->A), codon 26 (G-->A), codon 30 (G-->C), and codon 41/42 (-TCTT). These accounted for 85% in 80 beta-thalassemic alleles deciphered from 56 patients, including beta-thalassemia major and carriers, and 15% of alleles remained uncharacterized in these patients. Expression of the human beta-globin gene is regulated by an array of cis-acting DNA elements, including five DNase I hypersensitive sites (HSs) in the locus control region (LCR), promoters that incorporate certain silencer elements, and enhancers at 3' of the beta-globin gene. For detailed studies and to understand the molecular basis of beta-thalassemia, we studied two groups of subjects: a group of 12 patients from four families having beta-thalassemia major and carrier phenotype and a control group of 26 healthy individuals. In these two groups, we examined portions of the beta-globin gene locus control region HSs 1, 2, 3, and 4, which included the (CA)(x)(TA)(y) repeat motif, the (AT)(x)N(y)(AT)(z) repeat motif, the inverted repeat sequence TGGGGACCCCA, the promoter region of the (G)gamma-globin gene, an (AT)(x)(T)(y) repeat 5' of the silencer region, and the beta-globin gene and its 3' flanking region. We investigated the allelic sequence polymorphisms in these regions and their association with the beta-thalassemia mutations to know the possible genotype-phenotype relationship in beta-thalassemia patients. An analysis of cis-acting regulatory regions showed varied sequence haplotypes associated with some frequent beta-thalassemia mutations in this Eastern Indian population.

Adult↗
PubMed1976

Clinical, hematologic and biosynthetic studies in sickle cell-betao-thalassemia: a comparison with sickle cell anemia.

The diseases commonly confused with sickle cell anemia include sickle cell beta-thalassemia in which synthesis of betaA-chains are completely suppressed (HbS-betao-thalassemia). We obtained hematologic measurements and studied globin biosynthesis in five patients with this disorder and compared the results with those obtained in five patients with "mild" sickle cell anemia and seven individuals with sickle cell-beta-thalassemia having hemoglobin A levels of 20-30% (HbS-beta+-thalassemia). A distinction between HbS-betao-thalassemia and sickle cell anemia was not always possible on clinical, hematologic, or electrophoretic grounds. Thalassemia heterozygotes had hypochromia and microcytosis, not generally a feature of sickle cell anemia, although overlap of values did exist. The ratio of alpha to non-alpha, or alpha to betaS-chains in sickle cell anemia approximated unity, whereas patients with HbS-betao-thalassemia had a deficit of beta-chain production relative to that of the alpha-chain. The differentiation of HbS-betao-thalassemia and sickle cell anemia can be best made on the basis of family or biosynthetic study. We estimated the regional prevalence of HbS-betao-thalassemia to be 1:23,000 of the black population.

Adult↗
PubMed1985

Concomitant inheritance of alpha-thalassemia in beta 0- thalassemia/Hb E disease.

Concomitant inheritance of alpha-thalassemia in patients with beta 0-thalassemia/hemoglobin (Hb) E disease was detected by restriction endonuclease DNA mapping. Among 42 patients with beta 0-thalassemia/Hb E disease, seven were found to have an alpha-thalassemia-2 haplotype. Of these, five belonged to the rightward or 3.7-kb type of alpha-thalassemia-2 and the remaining two the leftward or 4.2-kb type. All the seven patients with alpha-thalassemia-2 haplotype had hemoglobin levels of 7.4 g/dl or above; those without detectable alpha-thalassemia had hemoglobin levels both higher and lower than 7.4 g/dl. The latter attended the clinic regularly, the former did occasionally. These findings suggest that concomitant inheritance of alpha-thalassemia can alleviate the severity of beta 0-thalassemia/Hb E disease. Failure to find alpha-thalassemia-1 haplotype in these patients suggests that concomitant inheritance of alpha-thalassemia-1 with beta 0-thalassemia/Hb E might lead to so mild a condition that the individuals do not present clinically. The fact that many patients without a detectable alpha-thalassemia haplotype also had hemoglobin levels of 7.4 g/dl or higher suggests that there are additional factors responsible for the mildness of beta 0-thalassemia/Hb E disease.

Adolescent↗
PubMed2006

Genotyping of alpha-thalassemia in microcytic hypochromic anemia patients from North India.

Microcytic hypochromic anemia is a common condition in clinical practice and alpha-thalassemia has to be considered as a differential diagnosis. Molecular diagnosis of alpha-thalassemia is possible by polymerase chain reaction. The aim of this study was to evaluate the frequency of alpha-gene numbers in subjects with microcytosis. In total, 276 subjects with microcytic hypochromic anemia [MCV<80fl; MCH<27pg] were studied. These include 125 with thalassemia trait, 48 with thalassemia major, 26 with sickle-cell thalassemia, 15 with E beta-thalassemia, 40 with iron-deficiency anemia, 8 with another hemolytic anemia, and 14 patients with no definite diagnosis. Genotyping for -alpha3.7 deletion, -alpha4.2 deletion, Hb Constant Spring, and a-triplications was done with polymerase chain reaction. The overall frequency of -alpha3.7 deletion in 276 individuals is 12.7%. The calculated allele frequency for a-thalassemia is 0.09. The subgroup analysis showed that co-inheritance of a-deletion is more frequent with the sickle-cell mutation than in other groups. We were able to diagnose 1/3 of unexplained cases of microcytosis as a-thalassemia carriers. The a-gene mutation is quite common in the Indian subcontinent. Molecular genotyping of a-thalassemia helps to diagnose unexplained microcytosis, and thus prevents unnecessary iron supplementation.

Anemia, Hypochromic↗
PubMed2006

Molecular and hematological profiles of hemoglobin EE disease with different forms of alpha-thalassemia.

We describe hematologic and DNA characterization of hemoglobin (Hb) E homozygote with various forms of alpha-thalassemia in Thai individuals. Altogether, 131 unrelated adult subjects with Hb EE at routine Hb analysis were studied. Forty-two cases were found to carry alpha-thalassemia with ten different genotypes. These included 21 cases with alpha(+)-thalassemia heterozygote (-alpha(3.7)/alphaalpha), one case with alpha(+)-thalassemia heterozygote (-alpha(4.2)/alphaalpha), six cases with Hb Constant Spring heterozygote (alpha(CS)alpha/alphaalpha), four cases with homozygous alpha(+)-thalassemia (-alpha(3.7)/-alpha(3.7)), one case with homozygous alpha(+)-thalassemia (-alpha(4.2)/-alpha(4.2)), two cases with compound alpha(+)-thalassemia/Hb Constant Spring (-alpha(3.7)/alpha(CS)alpha), one case with compound alpha(+)-thalassemia/Hb Paksé (-alpha(3.7)/alpha(PS)alpha), four cases with alpha(0)-thalassemia heterozygote (--(SEA)/alphaalpha), and, unexpectedly, two cases with compound alpha(0)-thalassemia/alpha(+)-thalassemia [(--(SEA)/-alpha(3.7)) and (--(SEA)/-alpha(4.2))]. The hematological expression of these Hb E homozygotes with various forms of alpha-thalassemia was presented comparatively with those of the 89 cases of pure Hb E homozygotes. Overlapping levels of Hb E, Hb F, and other hematological parameters were observed which did not predict clinical severity, indicating a need for alpha-globin gene analysis for accurate diagnosis and improved genetic counseling.

Genetic Variation↗
PubMed2005

Prevalence of fractures among the Thalassemia syndromes in North America.

Historically, fractures are cited as a frequent problem in patients with Thalassemia prior to optimization of transfusion and chelation regimens. The aim of this study was to determine the prevalence of fractures in a contemporary sample of North American patients with Thalassemia. The North American Thalassemia Clinical Research Network (TCRN) database registry was used to gather historical data on 702 patients with common alpha and beta-Thalassemia diagnoses including Thalassemia Major (TM), Intermedia (TI), E/Beta, homozygous alpha Thalassemia (AT), Hemoglobin H disease (HbH) and HbH with Constant Spring (HbH/CS), who consented to a medical record chart review. Bone mineral density (BMD) measurements by DXA were available for review in a subgroup of patients (n = 312). The overall fracture prevalence among all Thalassemia syndromes was 12.1%, equally distributed between females (11.5%) and males (12.7%). Fractures occurred more frequently in TM (16.6%) and TI (12.2%) compared to E/Beta (7.4%) and alpha (2.3%). Prevalence increased with age (2.5% ages 0-10 years, 7.4% ages 11-19 years, 23.2% ages >20 years) and with use of sex hormone replacement therapy (SHRT) (P < 0.01). On average, BMD Z and T scores were 0.85 SD lower among patients with a history of fractures (mean Z/T score -2.78 vs. -1.93, 95% CI for the difference -0.49 to -1.22 SD, P = 0.02). Presence of other endocrinopathies (i.e. hypothyroidism, hypoparathyroidism and diabetes mellitus), anthropometric parameters, heart disease or hepatitis C were not significant independent predictors of fractures. These data indicate that fractures remain a frequent complication among the aging patients with both TM and TI beta-Thalassemia. However, the fracture prevalence has improved compared to published reports from the 1960s to 1970s. In addition, children with Thalassemia appear to have low fracture rates compared to the general population.

Adolescent↗
PubMed2006

Pubertal evaluation of adolescent boys with beta-thalassemia major and delayed puberty.

OBJECTIVE: To examine the hormonal status of the hypothalamic-pituitary-gonadal axis in adolescent males with beta-thalassemia major. DESIGN: Controlled clinical study. SETTING: Tertiary referral teaching hospital. PATIENT(S): Thirty-three adolescent males with beta-thalassemia major. INTERVENTION(S): Basal LH, FSH, and T were examined. All individuals received 100 microg GnRH analogue. Four hours later the hormone levels were retested. Patients with beta-thalassemia and low T levels received hCG. MAIN OUTCOME MEASURE(S): The preintervention and postintervention levels of FSH, LH, and T were examined. RESULT(S): Of the 33 beta-thalassemia major adolescents, 17 had delayed puberty. The difference in basal LH, FSH, and T levels between delayed and normal puberty beta-thalassemia groups were statistically significant. These levels were significantly lower compared with the constitutional delayed puberty group and become even more significant after GnRH analogue administration. The T levels in the beta-thalassemia group were significantly lower than in the control group. After hCG administration, the T levels remained significantly lower in the delayed-puberty beta-thalassemia compared to the normal-puberty beta-thalassemia group. CONCLUSION(S): Despite recent therapeutic advances in the management of beta-thalassemia major, the risk of secondary endocrine dysfunction remains high. Hypogonadism is one of the most frequent endocrine complications.

Adolescent↗
PubMed2006

Effects of silymarin on the proliferation and glutathione levels of peripheral blood mononuclear cells from beta-thalassemia major patients.

Iron toxicity in beta-thalassemia major is the main cause of oxidative stress and cell mediated immune deficiencies. Despite indicative signs of severe oxidative deficiencies associated with beta-thalassemia major, such as decreased level of plasma antioxidants and depletion of erythrocyte glutathione, little is known about intracellular redox status of immune cells. Since glutathione is a primary intracellular antioxidant and plays an essential role in several functions in T cells, in this study intracellular glutathione (GSH) levels as well as proliferation of PHA-activated peripheral blood mononuclear cells (PBMC) were investigated in 28 beta-thalassemia major patients and 28 healthy age-matched individuals. Considering the potential benefits of flavonoids in the therapy of oxidative stress, the effects of silymarin on the GSH levels and proliferation of PBMC from normal and thalassemia individuals were further examined. Quantitative determination of intracellular GSH and proliferative response of PBMC to PHA were performed before and after 72 h incubation of PBMC with various concentrations of silymarin (0, 5, 10, or 20 mug/ml). Results demonstrated a significant reduction of GSH and proliferation in beta-thalassemia major cells; however treatment with silymarin led to restoration of both GSH levels and PBMC proliferation in thalassemia patients. Considerably low levels of GSH and depressed proliferative response of PBMC in beta-thalassemia major may be responsible for the cell mediated immune abnormalities in iron overload conditions. Moreover, the GSH restoration and improvement of PBMC growth by silymarin is a possible explanation for its recently reported antioxidant and immunostimulatory activities. These data suggest the benefit of using flavonoids to normalize immune dysfunction in beta-thalassemia major. The immunomodulatory effects of silymarin in beta-thalassemia major are currently under further investigation in a double blind clinical trial.

Adolescent↗
PubMed1975

Expression of the beta-thalassemia gene in the first trimester fetus.

To determine whether beta-thalassemia can be detected in the fetus, blood was obtained from abortuses of normal mothers and of mothers with beta-thalassemia trait. The red cells were incubated with radioactive leucine and the globin chains were analyzed by radiochromatography. Two independent methods were utilized to correct the results for contamination by maternal radioactive beta-chain, and the corrected beta/gamma ratios were compared to a previously established range of normal fetal beta/gamma synthetic ratios obtained by similar measurements in pure fetal cells. In the erythroid cells of three fetuses from mothers with beta-thalassemia trait, the beta/gamma synthetic ratio was normal in two. The third had a beta/gamma ratio of 0.04 at 10 1/2 weeks, a 50% reduction, consistent with fetal beta-thalassemia trait. Two other fetuses, derived from parents both of whom had beta-thalassemia trait, were also studied. One had a beta/gamma ratio of 0.029 at 8 weeks, a 65% reduction, also consistent with beta-thalassemia trait. The cells of the other had a ratio of essentially zero at 11 weeks, highly suggestive of homozygous beta-thalassemia. Although further experience will be needed to distinguish the homozygous and heterozygous states reliably, it now appears that the beta-thalassemia gene is expressed in the first trimester. Therefore these data suggest that the antenatal diagnosis of beta-thalassemia is becoming an attainable goal.

Female↗
PubMed2001

Prenatal diagnosis of beta-thalassemia major by high-performance liquid chromatography analysis of hemoglobins in fetal blood samples.

In Thailand and adjacent countries, most of the beta-thalassemia genes are beta(0)-thalassemia mutations that prevent the production of Hb A. We propose the quantitation of the Hb A fraction in fetal blood in the mid-trimester of pregnancy by automated high performance liquid chromatography as a reasonable prenatal diagnostic method to be applied in areas with limited laboratory facilities. Forty pregnant women at risk of delivering a child with beta-thalassemia major were identified using an erythrocyte osmotic fragility test and quantitation of Hb A2. Cordocentesis was performed at the gestational age of 18-22 weeks and fetal blood was analyzed for hemoglobin fractions by automated high performance liquid chromatography. The beta-globin gene mutations were characterized by beta-globin gene sequencing. The 4 bp deletion at codons 41/42 (-TTCT) was the most frequent of the 40 beta-thalassemia mutations observed (20/40 = 50%), followed by the splice site mutation IVS-I-1 (G-->T) (7/40 = 17.5%), the nonsense mutation at codon 17 (A-->T) (7/40 = 17.5%), the nonsense mutation at codon 35 (C-->A) (3/40 = 7.5%), and the beta(+)-thalassemia promoter mutation at -28 (A-->G) (3/40 = 7.5%). High performance liquid chromatography revealed nine fetuses which had only Hb F and no Hb A. All were homozygotes or compound heterozygotes for beta(0)-thalassemia mutations. In the remaining 31 fetuses, a Hb A peak was present in the chromatograms. One fetus with 0.5% Hb A was a compound heterozygote for the -28 (A-->G) and codons 41/42 (-TTCT) mutations. In the remaining 30 fetuses, the Hb A values ranged between 0.8 and 7.4%. Twenty of these, with a Hb A concentration of 1.82 +/- 0.49% (range 0.8-2.8%), were beta-thalassemia heterozygotes. The remaining 10 fetuses had Hb A values of 4.89 +/- 1.47% (range 2.9-7.4%) and normal beta-globin genes. The absence of Hb A in homozygotes or compound heterozygotes for beta(0)-thalassemia mutations and the presence of measurable amounts of Hb A in heterozygotes and normal homozygotes, permits the diagnosis of fetuses expected to develop postnatal beta-thalassemia major.

Adult↗
PubMed1988

Hematologic changes in alpha-thalassemia.

Alpha-thalassemia is very common in Thailand. Interaction of the different types of alpha-thalassemia can lead to many alpha-thalassemia syndromes. In this study the authors compare the hematologic data of subjects with various alpha-thalassemia phenotypes. Designation of the genotypes was based on family study and DNA mapping. The results show that there are equivocal hematologic findings among those who have similar molecular defects, i.e., alpha-thalassemia-2 and hemoglobin (Hb) Constant Spring heterozygotes: alpha-thalassemia 1, homozygous alpha-thalassemia 2, and alpha-thalassemia 2/Hb Constant Spring. The severity of these alpha-thalassemia syndromes correlates with the alpha-globin gene expression calculated from the finding of Liebhaber (Liebhaber SA, et al. J Biol Chem 1986; 261:15327-15333).

DNA↗
PubMed1996

Incidence of scoliosis in beta-thalassemia and follow-up evaluation.

STUDY DESIGN: One hundred fifteen of 120 patients with beta-thalassemia followed in the thalassemia unit were studied for the presence of scoliosis. Forty-nine of these patients were reevaluated 1 year later. OBJECTIVES: To determine the frequency and the course of scoliosis in beta-thalassemia and to compare the findings with those of patients with idiopathic scoliosis. SUMMARY AND BACKGROUND DATA: There is only one report indicating increased frequency of scoliosis in a limited number of patients with thalassemia. In this study, the authors assessed the frequency of scoliosis in a large sample of patients and followed the evolution of this spinal deformity. METHODS: Patients with beta-thalassemia aged 3-35 years were examined clinically and radiologically for scoliosis. Forty-nine of them were reexamined 1 year later for determination of the evolution of scoliosis. RESULTS: Lateral curves of at least 5 degrees Cobb were found in 77 patients (67%), with a male-to-female ratio of 0.9. Scoliosis of at least 10 degrees was found in 21.7% of the male and 20% of the female patients with thalassemia. The ratio was 1.18 for curves of at least 10 degrees and 0.77 for curves of a smaller magnitude. The most common curve pattern was the left lumbar (35.1%), followed by the double-curve pattern (16.9%). Forty-nine randomly selected patients (42.6%) of the 115 included in the study were reexamined 1 year later. Seven male and 7 female patients (total, 28.6%) showed a progression of at least 5 degrees. Six patients (12.2%) experienced spontaneous improvement of less than 6 degrees. The pattern and the evolution of scoliosis observed in patients with beta-thalassemia differ from those found in Greek children with idiopathic scoliosis. CONCLUSIONS: The findings of this study show that the incidence, evolution, and etiology of scoliosis in beta-thalassemia differ from those of idiopathic scoliosis, indicating that the spinal deformities in patients with beta-thalassemia represents a distinct type of scoliosis. Longer follow-up is needed to investigate the natural history of this type of scoliosis.

Adolescent↗
PubMedDate not supplied

Blunted serum erythropoietin response to anemia in patients polytransfused for beta-thalassemia major.

PURPOSE: To investigate the response of erythropoietin (EPO) to anemia in patients polytransfused for beta-thalassemia major. PATIENTS AND METHODS: We measured the serum EPO levels and the concurrent hemoglobin (Hb) concentrations in 40 patients polytransfused for beta-thalassemia major, in 18 patients with iron deficiency anemia (IDA), and 32 healthy subjects. Serum EPO levels were assayed by an enzyme immunoassay. RESULTS: In both groups with beta-thalassemia major and IDA, serum EPO levels were significantly elevated (114 +/- 71 and 239 +/- 217 mU/mL, respectively). There was a significant inverse correlation between log EPO values and Hb concentrations in patients with beta-thalassemia major (r = 0.61; p < 0.01) and IDA (r = 0.81; p < 0.01). In a semilogarithmic plot, the slope of the regression line obtained in patients with beta-thalassemia major was significantly lower than that of IDA (p < 0.01), suggesting a blunted EPO response to anemia in patients polytransfused for beta-thalassemia major. The elevation of serum EPO in patients with beta-thalassemia major was poorly related to clinical variables except serum ferritin. CONCLUSIONS: We conclude that a significant inverse relationship between serum EPO levels and Hb concentration exists in patients with beta-thalassemia major. However, this EPO response in patients with anemia caused by beta-thalassemia major may be blunted when compared to patients with IDA.

Adolescent↗
PubMedDate not supplied

Quantification of liver iron overload by T2 quantitative magnetic resonance imaging in thalassemia: impact of chronic hepatitis C on measurements.

PURPOSE: Measurement of liver T2 values seems to be an accurate and sensitive magnetic resonance imaging (MRI) method for the quantification of liver hemosiderosis in multiple transfused patients with thalassemia. Because many of these patients have coexistent chronic hepatitis C virus (HCV) infection, the effect of inflammatory changes on liver T2 values was assessed. MATERIALS AND METHODS: Liver MRI studies of 35 HCV+ and 17 HCV- patients with beta-thalassemia, 9 HCV+ patients without thalassemia, and 10 healthy controls of the same age range (13 to 32 years) were reviewed. Iron status was assessed by serum ferritin in all patients, and determination of liver iron concentration (LIC) was available in 16 HCV+ patients with thalassemia. Histologic activity index (HAI) and grades of siderosis were evaluated in all HCV+ patients with thalassemia. RESULTS: Patients with thalassemia had significantly lower T2 values (P < 0.0001) than subjects without thalassemia, whereas no difference existed between HCV+ patients without thalassemia and healthy controls. In HCV+ patients, LIC correlated more nearly with T2 values (r = 0.93) than with serum ferritin (r = 0.73). T2 values were not influenced by HAI score or fibrosis. CONCLUSION: Liver T2 values were found to be more accurate than serum ferritin in predicting liver iron overload and were not influenced by the presence of chronic hepatitis C. Therefore, MRI could serve as a noninvasive alternative to liver biopsy for the quantification of hemosiderosis in HCV+ patients with thalassemia.

Adolescent↗
PubMed1994

A 12-year preventive program for beta-thalassemia in Northern Sardinia.

From 1980 to 1991, 6.3% of the adult population of the province of Sassari, Northern Sardinia, underwent voluntary beta-thalassemia screening. Of the 28,000 subjects examined, 15.7% proved to be heterozygotes for beta-thalassemia. In addition, the screening of 7500 students in 26 villages in Sassari province fixed the frequency of beta-thalassemia in this part of Sardinia at 10.4%. Of the 539 couples at risk to be expected from this figure, the screening detected 43% (234). The data suggest that inductive screening played a major role in the efficiency of this preventive beta-thalassemia program. Follow up of 221 pregnancies found to be at risk for homozygous beta-thalassemia and referred to the Antenatal Diagnosis Service, Cagliari, Southern Sardinia, showed that antenatal diagnosis was carried out in 80% of them. The overall percentage of couples refusing antenatal diagnosis was 10.8%, but over the years the acceptance rate for the procedure increased from 87% to 96%. Atypical hematological findings in 1.5% of 468 members of the couples at risk required globin chain synthesis and molecular analyses to define the precise beta-thalassemia genotype. Heterogeneous "mild" beta-thalassemia mutations as well as coexisting delta-thalassemia were found in silent type I and type II beta-thalassemia carriers which, without chain synthesis and DNA investigations, would have escaped detection.

Genetic Counseling↗
PubMed2005

[Association of hemoglobinopathy and alpha thalassemia. Study of 45 patients].

BACKGROUND AND OBJECTIVE: Hemoglobin S (HbS) alpha-thalassemia together with ss-thalassemia and hemoglobins C, E and D are named common hemoglobinopathies. In this study, we analyzed the frequency of the association between alpha-thalassemia and HbS and its phenotypic expression. PATIENTS AND METHOD: Since January 1995 to March 2003 we studied 83 cases of HbS, which were diagnosed by electrophoretic and chromatographic criteria. The molecular study was carried out by Southern blot with the restriction enzymes Bam HI and Bgl II and a (1.5 Kb Pst) and z (1.8 Kb Sac Y) probes. RESULTS: 45 cases (54.2%) had a-thalassemia (36 -alpha3,7/aa; 1-alpha4,2/alphaalpha; 6 -alpha3,7/-alpha3,7; 1-alpha4,2/-alpha4,2); 36 had not alpha-thalassemia and in two cases there were a triplication of a genes. The patients with HbS heterozygote associated with alpha-thalassemia showed a percentage of HbS (p < 0.0001), CMV (p = 0.004), MCH (p = 0.002) and MCHC (p = 0.02) significantly lower than the cases of HbS without this association. However, no differences between both groups were found with regard to the rest of parameters analyzed (Hb p = 0.56; PVC p = 0.84; RDW p = 0.06; Reticulocytes p = 0.26; HbF p = 0.76; HbA2 p = 0.13). In the cases with a severe form of disease (HbS homozygote; HbS/Hb C; HbS/beta-thalassemia), patients with alpha-thalassemia had a number of leukocytes that was significantly lower than that of patients without alpha-thalassemia (p = 0.034). CONCLUSION: An association between HbS and alpha-thalassemia was common (> 50%). Screening for this association is of great interest because the clinical expression in the cases of HbS homozigote will be modulated. This association must be suspected in cases of homozygous HbS in which levels of HbS are lower than expected.

Anemia, Sickle Cell↗
PubMed1978

Different types of beta-thalassemia intermedia. A genetic study in 20 patients.

20 patients with beta-thalassemia intermedia classified according to the results of genetic studies are presented. (1) 9 patients with beta-thalassemia intermedia homozygous for beta-thalassemia with increased Hb-A2 are reported. (2) 8 patients with beta-thalassemia intermedia, 3 homozygous for beta-thalassemia with normal levels of Hbs.A2 and F, 5 heterozygous for both this and beta-thalassemia with increased Hb-A2 are presented. (3) 2 families with beta-thalassemia intermedia heterozygous for both beta-thalassemia with increased HbA2 and 'silent" beta-thalassemia are reported. Two different varieties are presented.

Adolescent↗