Detection of alpha-thalassemia in beta-thalassemia carriers and prevention of Hb Bart's hydrops fetalis through prenatal screening

The aim of this study was to detect alpha-thalassemia in beta-thalassemia carriers during prenatal screening. During a 12-year prenatal screening program, a total of 158 couples (3.2%) were diagnosed to be the discordant alpha- and beta-thalassemia carriers. Of the 158 beta-thalassemia partners, seven (4.4%) were found to have co-inheritance of alpha0-thalassemia, and three (1.9%) found to have co-inheritance of alpha(+)-thalassemia. Three pregnancies affected with Hb Bart's hydrops fetalis were terminated in the 158 couples. The results showed that molecular analysis must be used for accurate diagnosis of double heterozygotes in couples presumed to be discordant for alpha- and beta-thalassemia on hematologic testing.     

Prenatal diagnosis of beta-thalassemias by amniocentesis: linkage analysis using multiple polymorphic restriction endonuclease sites

In order to assess the applicability of multiple restriction endonuclease analyses of amniocyte DNA to the prenatal diagnosis of beta-thalassemias in general, we studied 12 consecutive couples at risk. DNA of both members of the 12 couples and a previous offspring of each was analyzed for the presence of 4 polymorphic restriction endonuclease sites: the Hpa I site 3' to the beta-globin gene, the Hind III site in the G gamma gene, the Hind III site in the A gamma gene, and the Bam HI site 3' to the beta-gene. Linkage disequilibrium between these sites and beta A or beta thal genes was not found, presumably due to the heterogeneity of beta thal genes. However, the high frequency of polymorphism at these sites allowed differentiation of beta A-bearing chromosomes from beta thal or beta S-bearing chromosomes in both members of 6 couples. In these couples, complete prenatal diagnosis by linkage analysis of amniocyte DNA would be possible. In the remaining 6 couples, beta A and beta thal chromosomes could be discriminated in one member. In about 50% of the pregnancies of these couples, exclusion of beta-thalassemia is possible by this analysis. These data suggest that when linkage analysis of polymorphic restriction endonuclease sites is carried out, prenatal diagnosis of beta-thalassemia states can be accomplished by amniocentesis alone in 75% of pregnancies at risk.     

On the origin and spread of beta-thalassemia: recurrent observation of four mutations in different ethnic groups.

Seven beta-thalassemia genes were characterized after they were identified as candidates for previously undescribed mutations based upon the close association of DNA polymorphism haplotypes in the beta-globin gene cluster with specific ethnic mutations. The molecular defect in four of these genes was identical, a frameshift deletion of four nucleotides (-CTTT) within codons 41 and 42. This gene represents a common Southeast Asian mutation shared by a Laotian beta-thalassemia gene, [framework 1 (FR1)], a Vietnamese (FR1), and two Chinese patients (FR3 Asian and FR1). The deletion has been observed previously in Chinese (FR1) and Asian Indians (FR2) and is an example of independent origins of the same molecular defect, possible interallelic gene conversion (as it is seen on two different beta-globin gene frameworks in Chinese), and mutant gene migration in the Asian countries. A second example of mutant gene migration was identified in an Iranian patient with a nucleotide insertion (G) between codons 8 and 9, the same mutation previously found in an Asian Indian in the same chromosomal background. The last two genes examined represent further strong evidence for independent origins of mutation. A C-to-T substitution at position -88 in an Asian Indian has been identified previously in an American Black on a different beta-globin gene framework, and a G-to-A transition at nucleotide 1 of intervening sequence 2 found in an American Black has been observed previously on a different chromosome background in Mediterraneans. This study suggests that there are not many common beta-thalassemia mutations remaining to be discovered. It also suggests that certain sequences in the beta-globin gene are relatively mutation sensitive.     

The homozygous state of Hb J Sardegna

Hb J Sardegna is a well known innocent Hb variant which is widespread in Sardinia. As yet, homozygosity for Hb J Sardegna has not been documented. This report deals with the homozygous state for Hb J which we demonstrate by molecular analysis in two Sardinian siblings in which beta-thalassemia coexists. The Hb J specific mutation was determined both by enzyme digestion and by sequencing specific segments of PCR amplified alpha-globin genes. A pregnant girl showed mild non-sideropenic microcytic anemia, normal Hb A(2) levels (2.4%) on DE-52 microchromatography, 50% of Hb variant on HPLC and 2.1 alpha/beta globin chain biosynthetic ratio. She proved to be a carrier of the beta degrees 6(-A) thalassemia determinant. The alpha-globin gene mapping did not reveal alpha-thalassemia. Btg I restriction analysis of both alpha(2)-globin genes showed a recognition site defect for this enzyme in both chromosomes, which resulted to be the C-->A point mutation in homozygosity at the first nt of alpha(2)-globin gene 50th codon by sequencing. This defect, typical of Hb J Sardegna, was also present in her brother. From a practical point of view, this study demonstrates that the association of beta-thalassemia with Hb J, may show falsely reduced Hb A(2) levels on routine Hb A(2) quantitation techniques, such as DE-52 microchromatography. This possibility implies that identification methods such as simple Hb electrophoresis, which permit visualization of Hb A(J)(2) should be used in thalassemia screening involving populations in which Hb J and beta-thalassemia coexist.     

Premarital screening of beta-thalassemia trait in the province of Denizli, Turkey

A premarital screening program aiming at reducing the incidence of thalassemia major was started under the auspices of the Regional Health Administration in 1995 in the city of Denizli in the Aegean region of Turkey. In this report we assessed the 4-year results of the screening program. All couples who applied for marriage procedures were screened for beta-thalassemia trait by automatic red cell indices and Hb A(2) determination. The couples at risk were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus. From October 1995 to August 1999, a total of 19,804 subjects (9,902 couples) were recruited for this study. The prevalence of beta-thalassemia trait with increased Hb A(2) was found to be 2.6% (514/19,804). In addition to the thalassemia trait, 22 patients (0.11%) had sickle trait. In 15 of the 9,902 couples, both partners were found to be carriers of the beta-thalassemia trait. After genetic counseling, 2 of the 15 planned carrier marriages were canceled. Seven couples declared that they do not want to have a child at present. Prenatal diagnosis was sought by 6 couples. One fetus was found to be normal, 4 had thalassemia minor and 1 had thalassemia major; this pregnancy was terminated by elective abortion. This study indicated that premarital screening is a very useful tool for detecting carrier couples and an effective way of controlling thalassemia major.     

Hb Johnstown [beta 109 (G11) Val-->Leu]: second case described and associated for the first time with beta(0)-thalassemia in two Spanish families

Hb Johnstown, a high oxygen affinity hemoglobin, was identified in four members from two unrelated Spanish families with erythrocytosis and left-shifted hemoglobin-oxygen dissociation curve. This hemoglobin variant, electrophoretically silent, was analyzed by reverse-phase high-performance liquid chromatography, and the mutation was characterized at the DNA level by beta gene sequencing. In one of these families, two members are affected with Hb Johnstown in association with beta(0)-thalassemia. In these cases the erythrocytosis and low values for P(50) due to Hb Johnstown remain in spite of the beta-thalassemia.     

Beta-thalassemia intermedia from southern Iran: IVS-II-1 (G-->A) is the prevalent thalassemia intermedia allele

The preliminary results of a pilot study are reported, intended as an initiation of a research plan, focused on the prevention of beta-thalassemia in Iran. The aims of this study are: (i) to improve the knowledge of the molecular background of beta-thalassemia intermedia in Southern Iran; (ii) to verify the role of the -158 (G)gamma (C-->T) (Xmn I) polymorphism as a modulating factor in thalassemia intermedia; (iii) to test the validity of the multiplex and single mutation specific amplification refractory mutation system in analyzing the molecular defects causing beta-thalassemia in multiethnic populations; and (iv) to develop suitable strategies for the application of prevention protocols in Iran. To accomplish the task we have selected 87 beta-thalassemia intermedia patients and adapted the DNA methodology to detect the following 11 frequent mutations in Iran: codon 5 (-CT); frameshift codons (FSC) 8/9 (+G); codon 30 (G-->C); IVS-I-1 (G-->A); IVS-I-5 (G-->C); IVS-I-6 (T-->C); IVS-I-110 (G-->A); codons 36/37 (-T); codon 44 (-C); IVS-II-1 (G-->A); IVS-II-745 (C-->G). Because of the multiethnicity of the population we have also included the Indian IVS-I (25 bp deletion) and the Mediterranean IVS-I-130 (G-->C) and codon 39 (C-->T) mutations. Forty-eight patients were randomly studied for the Xmn I polymorphism together with 50 healthy volunteers as a control group. The molecular analysis conducted in Iran, identified only 31% of the alleles that were presumed to be thalassemic, revealing either a strategic or a technical insufficiency of the chosen method. However, the mutations with the highest prevalence in the country (IVS-II-1, IVS-I-110, IVS-I-1 and FSC 8/9) were found. As expected the IVS-II-1 defect, being the most frequent in south Iran, was present at the highest rate (24%). The Xmn I polymorphism was found in association with this prevalent mutation and was detected in the homozygous state in 87.5% of the patients homozygous for the IVS-II-1 (G-->A) mutation. The overall positivity for Xmn I was found in 40.6% of the thalassemic alleles vs. 14% in the non-thalassemic, confirming the hypothesis of an older event, antecedent to the IVS-II-1 mutation. In trying to assess a more suitable molecular detection method we intend to continue this study in collaboration with the European centers involved, applying more effective technologies and better defining the molecular spectrum of beta-thalassemia in the sub-populations. We also intend to verify the effect of alpha-thalassemia in the genotype/phenotype correlation of beta-thalassemia intermedia.     

Characterization of a new polymorphism, IVS-I-108 (T-->C), and a new beta-thalassemia mutation, -27 (A-->T), discovered in the course of a prenatal diagnosis

We report two new substitutions, IVS-I-108 (T-->C) and -27 (A-->T), identified in a couple at risk for beta-thalassemia. One is of Iranian origin and presents with two mutations: a new substitution of T-->C at nucleotide IVS-I-108, which is a silent polymorphism, and a previously described beta-thalassemia mutation at nucleotide -28 (A-->C). The other is from the island of Corsica, the only place in France where beta-thalassemia is endemic. He presents a new substitution of A-->T at nucleotide -27 in the TATA box, which was also found in several members of his family with the beta-thalassemia trait. The fetus was found to have inherited both these novel mutations.     

Significance of borderline hemoglobin A2 values in an Italian population with a high prevalence of beta-thalassemia

We report a retrospective analysis carried out on 23,485 subjects submitted to a screening program from 2000 to 2006. Of these subjects, 3,934 had borderline HbA(2) values from 3.1 to 3.9%; 410 samples, analyzed previously using PCR methods and sequencing because all of these were partners of a carrier of classical beta-thalassemia, were selected for statistical analysis. Of 410 subjects, 94 (22.9%) were positive for a molecular defect in the beta-, delta- or alpha-globin genes. The most prevalent molecular defects were beta IVS1 nt 6 (HBB c.92+6T C), co-inheritance of severe beta thalassemia and delta mutations, beta-promoter mutations and triplication of alpha genes were detected; alpha-thalassemia and Hb-variants were also evident. Borderline HbA(2) is not a rare event in a population with a high prevalence of beta-thalassemia carriers. These data support the necessity to investigate these cases at a molecular level, particularly if the partner is a carrier of beta-thalassemia.     

Molecular characterization of thalassemia intermedia in Indians

Thalassemia intermedia shows considerable heterogeneity. The purpose of this study was to evaluate the prevalence and effect of common molecular determinants in thalassemia intermedia. In 73 cases of thalassemia intermedia, the possible molecular basis was co-existent a-deletions (n=16/50), homozygous XmnI polymorphism (n=17/50), both factors (n=3/50), and milder beta-alleles (n=9/50) in homozygous beta-thalassemia (total 50 cases). In heterozygous beta-thalassemia, alphaalphaalphaanti-3.7 triplication was the predominant factor (14/23 cases).     

Prevention and control of thalassemia in Ramathibodi Hospital, Thailand

Eight thousand seven hundred and thirty-six pregnant women were screened for thalassemia and hemoglobinopathies by mean corpuscular volume less than 80 femtolitres (fl). Three thousand six hundred and seventy women (42%) were MCV less than 80 fl. In this group there were 2,390 women (70%) who had positive Hb typing by high performance liquid chromatography (HPLC) such as beta-thalassemia major, beta-thalassemia hemoglobin E disease, beta-thalassemia trait, heterozygous and homozygous hemoglobin E, alpha-thalassemia-1 trait and hemoglobin H disease and 77% of their partners came and had hemoglobin typing done. Seventy-five couples at risk for having severely affected thalassemia fetuses were detected from this screening program. Prenatal diagnosis was performed in 58 couples (77.3%). Eight affected fetuses were detected. All pregnancies with affected fetuses except one with beta-thalassemia/HbE were terminated. There were 3 fetal losses (6%) as the result of prenatal diagnosis procedure.     

Prenatal diagnosis of thalassemia and hemoglobinopathies in Switzerland

During a 10-month period, 10 couples originating from Africa (3), the tropics (1) and the thalassemia-belt region (6), living in Switzerland, requested prenatal diagnosis of hemoglobinopathies. Hb SS (twice), Hb Bart's (Hydrops fetalis) and beta-thalassemia major were diagnosed either by gene mapping or by direct detection of the mutations in DNA amplified by the PCR procedure. Whenever it was possible to obtain fetal blood or tissue, diagnosis was confirmed. In one Vietnamese man, concomitant existence of alpha-thal 1 with beta-thalassemia resulted in an unusually high Hb level because of balanced alpha and beta globin synthesis. The 10 couples examined originated from 7 different countries and presented at least 7 different Hb pathologies. This variety of pathologies represents the main difficulty for prenatal diagnosis of hemoglobinopathies in a non-endemic country. A diagnostic approach to overcome this problem is developed.     

Preventation of thalassemia in Australia

Screening for thalassemia and other hemoglobinopathies in the major maternity hospitals in Melbourne, Australia has shown that 6% of the patient population carries a clinically significant genetic abnormality. The most common of these are beta-thalassemia (3%). HbS (1.8%), HbE (0.5%) and alpha0 thalassemia (0.4%). Approximately 60 prenatal diagnoses for the clinically significant combinations of these abnormal genes are performed annually in the 2 major centers of Melbourne and Sydney. The majority of these prenatal diagnoses are for beta-thalassemia major (65%). whilst 11% are for Bart's hydrops fetalis, 8% for HbE/beta-thalassemia. 6% for HbS/beta-thalassemia, 2% for sickle cell anemia and the remaining 8% for other combinations of thalassemia/hemoglobinopathies. Of the 178 patients with beta-thalassemia major, sickle cell disease or beta-thalassemia in combination with HbE or HbS, only 5 are less than 5 years old, reflecting both the success of the screening program and the increasing acceptance by couples of 1st trimester prenatal diagnosis.     

Beta-thalassemia in the Korean population

Beta-thalassemia is uncommon in the Korean population, however it must be considered in the differential diagnosis of hypochromic anemia. The molecular characterization of beta-thalassemia is absolutely necessary for molecular diagnosis as well as any genetic epidemiological study in this region. We analyzed the molecular basis of beta-thalassemia in 47 Korean families. Using direct sequencing of genomic DNA amplified through PCR and haplotype analysis, 44 beta-thalassemia genes were characterized, all of which were heterozygous. Fourteen different mutations were identified. The common mutations noted included the initiation codon (CD) ATG-->AGG (23.4%), CD 17 A-->T (21.2%), and IVS-II-1 G-->A (12.7%). Interestingly, mutations causing dominantly inherited beta-thalassemia were common (17.0%). All cases of IVS-II-1 G-->A mutations were linked to the silent mutation of CD 91 C-->T of the -globin gene. The initiation CD ATG-->AGG and IVS-II-1 G-->A with CD 91 C-->T were found in the Far East only, and may be inherited from a common origin for each mutation, at least in Koreans. CD17 A-->T and CDs 41/42-TTCT were suggested to be introduced by gene-flow from southern China. Otherwise, Hb Korea, CDs 89/90 -GT and a novel beta-thalassemia mutation, CD 131 CAG-->TAG, were only identified in Koreans. This mutation spectrum is characteristic of the low prevalent area of beta-thalassemia, however it is quite different even from the adjacent countries, Japan or China.     

X-linked syndrome of platelet dysfunction, thrombocytopenia, and imbalanced globin chain synthesis with hemolysis

An unusual family is described with a congenital bleeding disorder present in four males belonging to three generations. Of the three surviving affected males, all had splenomegaly and petechiae. The three had moderate thrombocytopenia (55-90 X 10(9)/liter) and markedly prolonged Ivy-template bleeding times (greater than 30 min). They were also noted to have reticulocytosis and, upon further investigation, imbalanced globin chain synthesis resembling that of beta-thalassemia minor. Studies on nine additional family members in four generations were normal except for slight elevations of reticulocyte counts in female members, one of whom had the abnormal globin chain synthesis ratio. In male members, the bleeding tendency and clinical signs always occurred in the presence of the globin chain synthesis defect and reticulocytosis. This previously undescribed condition was apparently transmitted as an X-linked disorder.     

beta-thalassemia intermedia caused by compound heterozygosity for Hb Malay (beta codon 19 AAC-->AGC; asn-->Ser) and codons 41/42 (-CTTT) beta(0)-thalassemia mutation

We report a case of beta-thalassemia intermedia caused by compound heterozygosity for hemoglobin (Hb) Malay and codon 41/42 (-CTTT) beta(0)-thalassemia mutation in a 38-year-old Chinese woman. This patient has long-standing anemia with a baseline Hb level of around 70 g/L. She worked as a full-time cashier and had not required regular blood transfusions. Nevertheless, she had splenomegaly necessitating splenectomy, cholelithiasis, and iron overload. This case illustrates the varied phenotypic expression associated with compound heterozygosity for Hb Malay and other beta-thalassemia mutations. Since Hb Malay migrates as Hb A on electrophoresis and chromatography, this variant Hb mutation ought to be included in the differential diagnosis for beta-thalassemia major or intermedia patients of Southeast Asian descent who are reported to have Hb A on the basis of Hb analysis. The possible presence of this mutation should also be considered in appropriate cases for genetic counseling in couples at risk of conceiving fetuses with beta-thalassemia major or intermedia.     

A rare example that coinheritance of a severe form of beta-thalassemia and alpha-thalassemia interact in a "synergistic" manner to balance the phenotype of classic thalassemic syndromes

The coinheritance of beta-thalassemia major with the genotype of Hb H disease is extremely rare, with few reported cases. We investigated the hematological, biochemical, biosynthetic, molecular and pathophysiological parameters to evaluate a rare male patient with this compound syndrome. The patient was studied at first diagnosis during hospitalization at 50 years of age and subsequently followed up for more than a year. Examinations included full hematological, biochemical, biosynthetic, molecular, pathophysiological and clinical parameters. Besides standard parameters, we additionally measured reticulocyte hemoglobin content (CHr), erythropoietin (Epo), soluble transferrin receptors (sTfR), oxygen pressure at 50% hemoglobin saturation (P50), 2,3-bisphosphoglycerate (2,3-BPG), total glutathione (GSHt), oxidized glutathione (GSSG), malonyldialdehyde (MDA), nontransferrin-bound iron (NTBI), vitamins A and E. The male patient was first hospitalized for a 2-day period at 50 years of age, following the finding of marked anemia (hematocrit 20%) during a blood test to investigate the cause of fatigue in the absence of weight-loss or other notable symptomatology. He had never been transfused, maintaining Hb 85-95 g/l. Definitive diagnosis was achieved through DNA studies, which showed coexistence of beta-thalassemia major (IVSI-6 T > C/IVSI-I G > A) with Hb H disease (-alpha(3.7)/-(Med)). Alpha/non-alpha globin chain biosynthesis was completely balanced. Parameters demonstrated a well-compensated anemia with ineffective erythropoiesis and oxidative stress, which was ameliorated following splenectomy. In conclusion, this case is a remarkable example that the coinheritance of severe forms of beta-thalassemia and alpha-thalassemia interact in a "synergistic" manner to almost complete balance the symptoms of classic thalassemia syndromes.     

Molecular analysis of beta-thalassemia in South Vietnam

In Vietnam, the carrier rate for beta-thalassemia varies from 1.5% to 25% depending on the ethnic groups of the population. The molecular basis of beta-thalassemia in South Vietnam was studied in 50 unrelated beta-thalassemia patients. Of these, 31 had beta-thalassemia/Hb E, 18 were homozygous for beta-thalassemia, and 1 carried the beta-thalassemia trait. The majority of the patients were Kinh, four were Chinese, and two were Kinh-Chinese. All had severe anemia and received blood transfusions regularly, every 1-3 months. Hepatosplenomegaly was found in all patients, and splenectomy had been done in six patients. Normal alpha-globin genotype (alpha alpha/alpha alpha) was found in all subjects. Reverse dot-blot hybridization using oligonucleotide probes specific for Southeast Asian mutations can detect beta-thalassemia in 60 chromosomes in addition to 31 chromosomes with beta(E) mutation. Excluding the beta(E) gene, six previously reported Thai and Chinese beta-thalassemia mutations were found, including codons 41/42 (-TCTT) 35.3%, codon 17 (A-->T) 25.0%, -28 (A-->G) 7.3%, codons 71/72 (+A) 7.3%, IVS-II nt 654 (C-->T) 7.3%, and IVS-I nt 1 (G-->T) 6.0%. The Vietnamese frameshift mutation at codon 95 (+A) was detected by ARMS in seven chromosomes (10.3%). DNA polymorphism of the beta-globin gene cluster carrying the codon 95 mutation was - + - - - - - + for (G)gamma/XmnI, epsilon/HincII, (G)gamma/HindIII, (A)gamma/HindIII, psi beta/HincII, 3' psi beta/HincII, beta/AvaII, and 3'beta/BamHI, respectively. The remaining mutation detected by the gap PCR was a large deletion known as the Chinese (G)gamma((A)gamma delta beta)(0)-thalassemia. The two most common mutations were the frameshift at codons 41/42 (-TCTT) and the nonsense mutation in codon 17 (A-->T). Thus beta-thalassemia mutations in South Vietnam is similar to the previous report from the North, although at different frequencies. This result will help to establish a center for prenatal diagnosis and for prevention and control of thalassemia in Vietnam.     

A multi-center study in order to further define the molecular basis of beta-thalassemia in Thailand, Pakistan, Sri Lanka, Mauritius, Syria, and India, and to develop a simple molecular diagnostic strategy by amplification refractory mutation system-polymerase chain reaction.

The spectrum of the beta-thalassemia mutations of Thailand, Pakistan, India, Sri Lanka, Mauritius and Syria has been further characterized by a multi-center study of 1,235 transfusion-dependent patients, and the mutations discovered used to assess the fidelity of a simple diagnostic strategy. A total of 44 beta-thalassemia mutations were identified either by allele-specific oligonucleotide hybridization, amplification with allele-specific primers, or DNA sequencing of amplified product. The results confirm and extend earlier findings for Thailand, Pakistan, India, Mauritius and Syria. This is the first detailed report of the spectrum of mutations for Sri Lanka. Two novel mutations were identified, codon 55 (-A) and IVS-I-129 (A-->C), both found in Sri Lankan patients. Two beta-thalassemia mutations were found to coexist in one beta-globin gene: Sri Lankan patients homozygous for the beta0 codon 16 (-C) frameshift were also homozygous for the beta+ codon 10 (C-->A) mutation. Studies of Sri Lankan, Pakistani, and Indian carriers suggest the codon 10 (C-->A) mutation is just a rare polymorphism on an ancestral allele, on which the beta0 codon 16 (-C) mutation has arisen. Each country was found to have only a few common mutations accounting for 70% or more of the beta-thalassemia alleles. A panel of primers to diagnose the majority of the mutations by the amplification refractory mutation system was developed, enabling a simple molecular diagnostic strategy to be introduced for each country participating in the multi-center study.     

Coexistence of Southeast Asian ovalocytosis and beta-thalassemia: a molecular and hematological analysis

We describe hematological and molecular characterization of a Thai female who had Southeast Asian ovalocytosis (SAO) associated with beta+-thalassemia trait. The proband had mild microcytosis with Hb 12.9 g/dl, Hct 35.8%, MCV 74.4 fl, MCH 26.8 pg, MCHC 36.0 g/dl, and elevated Hb A2 (5.6%), characteristics of beta-thalassemia trait. Peripheral blood film examination revealed prominent ovalocytosis. However, a one-tube osmotic fragility (OF) test commonly used for thalassemia screening was negative and a normal OF curve was observed. Further polymerase chain reaction (PCR) analyses identified the beta(-28A-G) mutation in the beta-globin gene and a 27 bp deletion in erythrocyte band 3 protein gene, indicating a genetically compound heterozygote. Hematological data of the proband was comparatively presented with those of eight female and 15 male carriers of pure beta-thalassemia with the same mutation. The finding demonstrates that although the association of the SAO and beta-thalassemia does not produce a more severe clinical picture, this could lead to a mis-screening of beta-thalassemia using an OF test as a primary screening test. Additional blood film examination followed by PCR could help in the detection of this unusual genetic interaction in the region.