Αlpha-thalassemia: A practical overview.

α-Thalassemia is an inherited blood disorder characterized by decreased synthesis of α-globin chains that results in an imbalance of α and ß globin and thus varying degrees of ineffective erythropoiesis, decreased red blood cell (RBC) survival, chronic hemolytic anemia, and subsequent comorbidities. Clinical presentation varies depending on the genotype, ranging from a silent or mild carrier state to severe, transfusion-dependent or lethal disease. Management of patients with α-thalassemia is primarily supportive, addressing either symptoms (eg, RBC transfusions for anemia), complications of the disease, or its transfusion-dependence (eg, chelation therapy for iron overload). Several novel therapies are also in development, including curative gene manipulation techniques and disease modifying agents that target ineffective erythropoiesis and chronic hemolytic anemia. This review of α-thalassemia and its various manifestations provides practical information for clinicians who practice beyond those regions where it is found with high frequency.

Newborn Screening and Clinical Profile of Children With Sickle Cell Disease in a Tribal Area of Gujarat.

OBJECTIVE: To present the result of newborn sickle cell disease (SCD) screening and clinical profile of SCD newborns in a tribal area of Gujarat. METHODS: We screened all newborns of sickle cell trait (SCT) and SCD mothers for SCD using high-performance liquid chromatography (HPLC) within two days of birth at a secondary care hospital in a tribal area in Gujarat from 2014 to 2019. Newborns with SCD were registered under an information technology based platform for hospital-based comprehensive care. Neonates were followed prospectively every 3 months. If they missed the clinic visit, a medical counsellor visited them at home to collect the required information. RESULTS: Out of 2492 newborns screened, 87 (3.5%) were diagnosed with SCD. Among the 67 newborns screened for alpha-thalassemia deletion, 64 (95.4%) of babies had alpha-thalassemia deletion. We recorded total 554 clinic visits over the period of 221.5 person-years. The rates of acute febrile illness, painful crisis, hospitalization and severe anemia were 42.9, 14.9, 14.9 and 4.5 per 100 person-year, respectively. Two deaths were recorded, and 5 babies (5.7%) had severe SCD. CONCLUSION: We found a high prevalence of alpha thalassemia deletion among newborn SCD cohort in tribal area of Gujarat, and 70% babies had atleast one clinical complication on follow-up.

Utilization of Discriminant Formulas in the Differentiation of Alpha Thalassemia, Beta Thalassemia, and Iron Deficiency in Premarital Setting.

BACKGROUND: Iron deficiency and thalassemia are two commonly encountered microcytic and hypochromic anemias. The primary objective was to find the best discriminant formula between alpha thalassemia and iron deficiency to be used in premarital screening centers. The secondary objective, was to find cutoff values that might differentiate alpha thalassemia, beta thalassemia, and iron deficiency collectively. METHODS: A total of 224 females divided into four groups (normal, alpha thalassemia, beta thalassemia, and iron deficiency) were recruited in this study after carrying out complete blood count, hemoglobin electrophoresis, serum ferritin, and molecular analysis. Based upon the laboratory data, 26 discriminant formulas (DF) were applied to differentiate alpha thalassemia, beta thalassemia, and iron deficiency anemia. Receiver Operating Characteristic (ROC) curve was constructed and sensitivity, specificity, and Youden's index were determined. RESULTS: In this study, Shine and Lal, Ehsani, Telissani, Sirachainan, Hisham, Kandhro 2, and Mantos indexes showed 100% sensitivity, specificity, Youden's index, and 1.00 AUC for differentiating alpha thalassemia from iron deficient group. Formulas that showed best sensitivity and specificity (100%) in the discrimination of beta thalassemia and iron deficiency were Mentzer, Shine & Lal, Sarivastava & Bevington, and Sirachainan index (AUC 1.00). AUC of Mentzer index was lower (0.988 vs. 1.00) in differentiating alpha thalassemia and iron deficiency than beta thalassemia and iron deficiency. CONCLUSIONS: Almost all discriminant formulas can be utilized for the prediction of microcytic anemia in a premarital setup after excluding beta thalassemia; however, further confirmation is mandatory for genetic counselling and iron supplementation. Furthermore, Bordbar, Kerman index I, and Huber-Herklotz index showed the lowest performance in the discrimination of alpha thalassemia and iron deficiency.

Haemoglobin Constant Spring (HbA2: c.427T>C) and Haemoglobin Adana (HbA2: c.179G>A) in jaundiced Malaysian term neonates with clinically significant hyperbilirubinemia.

INTRODUCTION: Haemoglobin Constant Spring (Hb CoSp) and Haemoglobin Adana (Hb Adana), are two non-deletion type of α-thalassemia reported in Malaysia. Owing to their structural instability, they cause hemolysis and hyperbilirubinemia. This observational study was part of a large study investigating multiple factors associated with severe neonatal jaundice. In this part we aimed to determine the prevalence of Hb CoSp and Hb Adana and their association with clinically significant neonatal hyperbilirubinemia (SigNH, total serum bilirubin (TSB>290µmol/L)) among jaundiced Malaysian term neonates. MATERIALS AND METHODS: The inclusion criteria were normal term-gestation neonates admitted consecutively for phototherapy. PCR-restriction fragment length polymorphism method was applied on DNA extracted from dry blood spot specimens of each neonate to detect for Hb CoSp and Hb Adana gene. Positive samples were verified by gene sequencing. RESULTS: Of the 1121 neonates recruited (719 SigNH and 402 no-SigNH), heterozygous Hb CoSp gene was detected in only two (0.27%) neonates. Both were SigNH neonates (0.3% or 2/719). No neonate had Hb Adana variant. CONCLUSION: Hb CoSp was not common but could be a risk factor associated with SigNH. No Hb Adana was detected.

Sickle cell screening in Uganda: High burden, human immunodeficiency virus comorbidity, and genetic modifiers.

BACKGROUND: The Uganda Sickle Surveillance Study provided evidence for a large sickle burden among HIV-exposed infants in Uganda. To date, however, no large scale screening program has been developed for Central or East Africa. METHODS: A 3-year targeted sickle cell screening project in Uganda was designed by the Ministry of Health to (1) determine sickle cell trait and disease prevalence within high-burden districts, (2) document the prevalence among HIV-exposed and nonexposed children, (3) confirm previously suggested HIV comorbidity, and (4) estimate the co-inheritance of known genetic modifiers of sickle cell disease. RESULTS: A total of 163 334 dried blood spot samples collected between April 2015 and March 2018 were analyzed, including 112 352 samples within the HIV Early Infant Diagnosis program. A high burden with >1% sickle cell disease was found within targeted East Central and Mid-Northern districts, in both HIV-exposed and nonexposed children. Based on crude birth-rate data, 236 905 sickle cell trait births and 16 695 sickle cell disease births will occur annually in Uganda. Compared to sickle cell disease without HIV, the odds ratio of having sickle cell disease plus HIV was 0.50 (95% confidence interval = 0.40-0.64, P < .0001). Alpha-thalassemia trait and G6PD deficiency were common with sickle cell disease, but with different geospatial distribution. CONCLUSIONS: High sickle cell burden and potential HIV comorbidity are confirmed in Uganda. Genetic modifiers are common and likely influence laboratory and clinical phenotypes. These prospective data document that targeted sickle cell screening is feasible and effective in Uganda, and support development of district-level comprehensive care programs.

[Application of multiplex ligation-dependent probe amplification technique in prenatal diagnosis of α-thalassemia].

OBJECTIVE To assess the application value of multiplex ligation-dependent probe amplification (MLPA) for the detection of gene deletion and prenatal diagnosis of α-thalassemia. METHODS MLPA was applied for 2 cases with α-thalassemia phenotype by whole blood cell counting and hemoglobin component detection but were ruled out by regular molecular diagnosis. Potential gene deletions and point mutations of α-thalassemia gene were detected with regular Gap-polymerase chain reaction (Gap-PCR) and reverse dot blotting (RDB) in 89 cases where one or both partners were carriers of α-thalassemia mutations. Meanwhile, MLPA was used for detecting α-globin gene deletion among the 89 samples. RESULTS For the 2 cases with α-thalassemia phenotype, no α globin gene deletion was detected by MLPA, but were subsequently confirmed as iron-deficiency anemia. The results of MLPA and Gap-PCR detection for the 88 cases were consistent, except for 1 fetal sample (chorionic villi) which could not be diagnosed by Gap-PCR and was confirmed to be - SEA/αα by MLPA. CONCLUSION MLPA can be applied to prenatal diagnosis of α-thalassemia as an effective supplement to Gap-PCR to reduce both misdiagnosis and missed diagnosis and improve the accuracy of prenatal diagnosis.

Discrimination of various thalassemia syndromes and iron deficiency and utilization of reticulocyte measurements in monitoring response to iron therapy.

Decreased hemoglobinization of red cells resulting in hypochromia and microcytosis are the main features of thalassemia syndromes, and also of iron deficiency anemia (IDA). A simple and reliable method is required to distinguish the two conditions in the routine laboratories. In this study we analyzed the red cell and reticulocyte parameters from 414 samples of various types of thalassemias and IDA and discovered a variety of discriminating criteria including a discrimination index (DI) which should be useful for differential diagnosis. Slightly decreased MCV and CH are suggestive of α-thalassemia 2, Hb CS, and Hb E heterozygotes whereas the increased Rbc counts are obvious in α-thalassemia 1 and ß-thalassemia. In Hb E, the number of microcytic red cells was greater than the number of hypochromic red cells resulting in an increased M/H ratio. Hb H diseases are characterized by a higher number of hypochromic red cells and decreased CHCM, while broadening of hemoglobin concentration histogram results in increased HDW in ß-thalassemia diseases. Iron deficiency anemia results in hypochromic-microcytic red cells and increased RDW. The number of reticulocyte with %High Retic and CHr value were increased in the first month of iron supplementation indicating the response to iron therapy.

Severe megaloblastic anaemia in an infant.

Vitamin B(12) or cobalamin deficiency, a rare clinical entity in pediatric age, is found most exclusively in breastfed infants, whose mothers are strictly vegetarian non-supplemented or with pernicious anaemia. In this article, the authors describe a 10-month-old infant admitted for vomiting, refusal to eat and prostration. The infant was exclusively breastfed and difficulties in introduction of new foods were reported. Failure to thrive since 5 months of age was also noticed. Laboratory evaluation revealed severe normocytic normochromic anaemia and cobalamin deficit. A diagnosis of α-thalassemia trait was also made. Maternal investigation showed autoimmune pernicious anaemia. This case shows the severity of vitamin B(12) deficiency and the importance of adopting adequate and precocious measures in order to prevent potentially irreversible neurologic damage.

Alpha and beta thalassemia.

The thalassemias are a group of inherited hematologic disorders caused by defects in the synthesis of one or more of the hemoglobin chains. Alpha thalassemia is caused by reduced or absent synthesis of alpha globin chains, and beta thalassemia is caused by reduced or absent synthesis of beta globin chains. Imbalances of globin chains cause hemolysis and impair erythropoiesis. Silent carriers of alpha thalassemia and persons with alpha or beta thalassemia trait are asymptomatic and require no treatment. Alpha thalassemia intermedia, or hemoglobin H disease, causes hemolytic anemia. Alpha thalassemia major with hemoglobin Bart's usually results in fatal hydrops fetalis. Beta thalassemia major causes hemolytic anemia, poor growth, and skeletal abnormalities during infancy. Affected children will require regular lifelong blood transfusions. Beta thalassemia intermedia is less severe than beta thalassemia major and may require episodic blood transfusions. Transfusion-dependent patients will develop iron overload and require chelation therapy to remove the excess iron. Bone marrow transplants can be curative for some children with beta thalassemia major. Persons with thalassemia should be referred for preconception genetic counseling, and persons with alpha thalassemia trait should consider chorionic villus sampling to diagnose infants with hemoglobin Bart's, which increases the risk of toxemia and postpartum bleeding. Persons with the thalassemia trait have a normal life expectancy. Persons with beta thalassemia major often die from cardiac complications of iron overload by 30 years of age.

Microcytic hypochromic anemia patients with thalassemia: genotyping approach.

BACKGROUND: Microcytic hypochromic anemia is a common condition in clinical practice, and alpha-thalassemia has to be considered as a differential diagnosis. AIMS: This study was conducted to evaluate the frequency of alpha-gene, beta-gene and hemoglobin variant numbers in subjects with microcytic hypochromic anemia. SETTING AND DESIGNS: Population-based case-control study in the Iranian population. MATERIALS AND METHODS: A total of 340 subjects from southwest part of Iran were studied in the Research Center of Thalassemia and Hemoglobinopathies (RCTH), Iran. Genotyping for known alpha- and beta-gene mutations was done with gap-PCR and ARMS. In cases of some rare mutations, the genotyping was done with the help of other techniques such as RFLP and ARMS-PCR. STATISTICAL ANALYSIS: Statistical analysis was carried out by SPSS 11.5 and an independent-sample t test. RESULTS: Out of the total 340 individuals, 325 individuals were evaluated to have microcytic hypochromic anemia based on initial hematological parameters such as MCV<80 fl; MCH<27 pg; the remaining 15 patients were diagnosed with no definite etiology. The overall frequency of -alpha3.7 deletion in 325 individuals was 20.3%. The most frequent mutations were IVS II-I, CD 36/37 and IVS I-110 with frequencies of 6.31%, 5.27% and 1.64%, respectively. Only, there was a significant difference between beta-thalassemia trait and beta-thalassemia major with regard to MCV (P<0.05) and MCH (P<0.05) indices, and also MCH index between beta-thalassemia trait and Hb variants (P<0.05). CONCLUSION: Molecular genotyping provides a rapid and reliable method for identification of common, rare and unknown alpha- and beta-gene mutations, which help to diagnose unexplained microcytosis and thus prevent unnecessary iron supplementation.

[Anaemia in adopted children, not always iron deficiency]. / Anemie bij adoptiekinderen, niet altijd ijzergebrek.

Anaemia was diagnosed in four adopted children during a standard screening examination 1-4 weeks after arrival. Further investigation revealed a number of causes which could then be specifically treated. The children were a girl aged 14 months from China with iron-deficiency anaemia, a boy aged 16 months from Nigeria with sickle cell anaemia, a girl aged 5 from Haiti who had alpha-thalassaemia, and a boy aged 7 from Brazil with spherocytosis. Iron deficiency is the most common cause of anaemia in childhood. However, in adopted children from sub-tropical areas other causes of anaemia like haemoglobinopathies or erythrocyte membrane defects should be borne in mind, particularly as a history of disease and family history are often lacking. Additional investigations may be necessary. An incorrect diagnosis of iron deficiency may result in ongoing and unjustified iron supplementation leading to harmful iron accumulation in thalassaemia and a delay in the correct treatment in sickle cell anemia or spherocytosis which could carry considerable risk.

[Transfusion in patients with hemoglobinopathies]. / Transfusion des patients atteints d'hémoglobinopathies.

A-Thalassemia involves a production deficiency concerning the synthesis of alpha-globin chains, and beta-thalassemia involves the beta-globin chains. Only a few patients in France are affected by the major form of thalassemia (certain types of homozygotic beta-thalassemia). Also, the systematic screening of 'at-risk' couples and prenatal diagnosis has helped to considerably reduce the incidence of new cases. The decision to perform regular blood transfusions is made when Hb levels fall below values that are compatible with normal activity. Hb levels above 10 g/dL permit normal educational, recreational and professional activity. This level is generally maintained via a 15 mL/kg erythrocyte concentrate supplement every three weeks, or 20 mL/kg every four weeks. However, the appearance of antierythrocytic autoantibodies is possible, and this may also result in an increase in blood transfusion requirements. In intermediate thalassemia patients, residual Hb levels are maintained at between 7 and 10 g/dL, and transfusion of erythrocyte concentrates is only made in the case of aggravation of chronic anemia or when there are signs of intolerance to chronic anemia. In France, there is relatively large population of patients with sickle cell disease. Blood transfusion is a major element in the treatment of these patients. Simple transfusion is performed in cases of a lack of iron or folates, increased hemolysis, splenic sequestration or parvovirus 19 infection. The target hematocrit should mostly remain at the patient's baseline value. Exchange transfusions are not performed on a regular basis, but only in cases of stroke or other severe vaso-occlusive events, or when a patient has to be prepared for surgery. A minority of subjects are involved in chronic blood transfusion, which is used mostly to prevent cerebrovascular accidents but also in cases of cardiac, renal, or respiratory insufficiency. There is an increased prevalence of antierythrocytic alloimmunization in sickle cell patients, most probably because of the discrepancies in red cell antigens between mainly Caucasian blood donors and Afro-Caribbean recipients.