Optimizing the Dose of Hydroxyurea Therapy for Patients with β-Thalassemia Intermedia (Hb E-β-thalassemia): A Single Center Study from Eastern India

Over the past 20 years, hydroxyurea (HU) has emerged as an important therapeutic agent to augment Hb F and thus total hemoglobin (Hb) in Hb E [β26(B8)Glu→Lys; HBB: c.79G>A]-β-thalassemia (Hb E-β-thal), albeit used in varying doses with little consensus on its optimal dose. We report the interim analysis findings of a broader study to assess the impact of Comprehensive Thalassemia Care, of which the present report was a part. Sixty-one Hb E-β-thal patients who were transfusion independent or requiring occasional transfusions [β-thal intermedia (β-TI)] were randomized to one of two groups; A (n?=?32) and B (n?=?29) to receive 10 and 20?mg/kg/day HU, respectively. The primary objective of the study was to assess the differences in responses to different doses of HU. Secondary end points were to see the tolerability and safety of HU in different doses. Good response (GR) was defined as a rise of Hb by >1.0?g/dL; intermediate response (IR) as a rise in Hb by 0.6–1.0?g/dL anytime during the study period. No response (NR): rise in Hb by <0.5?g/dL in 12 weeks or drop in Hb level from the previous value. Over a follow-up period of 24 weeks, we had 18 (56.2%) GRs, nine (28.2%) IRs and five (15.6%) NRs, while the number of GRs, IRs and NRs in group B were five (17.2%) 12 (41.4%) and 12 (41.4%), respectively. Adverse effects were more common in group B, making this dose (20?mg/kg/day) of HU more myelo-suppressive than Hb F inducing.     

Agro‐ecological zone and farm diversity are factors associated with haemoglobin and anaemia among rural school‐aged children and adolescents in Ghana

Understanding contextual risk factors for haemoglobin (Hb) status and anaemia of rural school‐aged children (SAC) and adolescents is critical in developing appropriate interventions to prevent anaemia. We analysed secondary data from the baseline of an impact evaluation of the Ghana School Feeding Programme to determine the severity of anaemia and contextual factors associated with anaemia and Hb status among rural SAC (6–9 years; n = 323) and adolescents (10–17 years; n = 319) in Ghana. We used regression models with variable selection based on backward elimination in our analyses. The mean Hb was 113.8 ± 13.1 g/L, and the overall prevalence of anaemia was 52.3%, being 55.1% and 49.5% among SAC and adolescents, respectively. We identified child's age (β = 2.21, P < 0.001); farm diversity score (β = 0.59, P = 0.036); and agro‐ecological zone (P trend <0.001) as the main predictors of Hb of SAC. Household asset index (P trend = 0.042) and agro‐ecological zone (P trend <0.001) were predictors of Hb in adolescents. Agro‐ecological zone and age were predictors of anaemia, but the effect of age was only significant for girls and not boys (prevalence odds ratio [POR] = 1.35, 95% CI [1.04, 1.76] vs. POR = 1.14, 95% CI [0.88, 1.46]). SAC in households with maize stock were less likely to be anaemic (POR = 0.55, 95% CI [0.32, 0.97]). Household dietary diversity score (β = 0.59, P = 0.033) was associated with Hb status for the full sample only. Anaemia is a severe public health problem among SAC and adolescents in rural Ghana irrespective of sex. Farm diversity score, availability of maize stock in the household, household asset index, and agro‐ecological zone were the main predictors of Hb and anaemia among the rural SAC and adolescents.     

Two Unstable β Chain Variants Associated with β-Thalassemia: Hb Miami [β116(G18)His→Pro], and Hb Hershey [β70(E14)Ala→Gly], and a Second Unstable Hb Variant at β70: Hb Abington [β70(E14)Ala→Pro]

We report on three previously undescribed unstable hemoglobin (Hb) variants: Hb Miami, Hb Hershey and Hb Abington. Hb Miami was associated with a β⁺-thalassemia (thal) mutation [IVS-I-110 (G→A)], whereas Hb Hershey was associated with a β⁰-thal mutation [IVS-I-1 (G→A)]. Hb Hershey also has decreased oxygen affinity. These three Hb variants illustrate the range of clinical severity that can be seen with unstable Hb variants, particularly when combined with a thalassemic mutation.     

Phenotype and Genotype Frequency of β-Thalassemia and Sickle Cell Disease Carriers in Halkidiki,Northern Greece

A decade of screening (years 2000 to 2010) for hemoglobinopathies in 3,931 patients was performed at the General Hospital of Poligiros, Halkidiki, Northern Greece. Among the patients examined, 10.8% heterozygotes for β-thalassemia (β-thal) were found, as well as 4.1% with sickle cell disease and 1.2% with double β-thal/Hb S [β6(A3)Glu→Val] heterozygosity. Iron deficiency was observed in 23.4%.

The geographical distribution in the region revealed a substantial incidence of hemoglobinopathies even in mountainous areas. This pattern did not follow the typical distribution according to the malaria hypothesis, as incidence did not dovetail with swamp locations recorded in the past.

The HBB gene mutations for 85 patients were also analyzed. Most prevalent in Halkidiki, Northern Greece, was the codon 39 (C>T) mutation (27.1%) followed by the IVS-I-110 (G>A) mutation (22.4%); this was in direct contrast to the current distribution of the same mutations seen in the rest of Greece (Greek National Genetic Database, GNGD). This frequency inversion was statistically significant, with the difference from the GNGD being 20.6% for the IVS-I-110 mutation (p <0.0005) and 7.6% for the codon 39 mutation (p = 0.0238). The history of Halkidiki, denoting a clear example of geographical isolation from the rest of the country, may possibly account for a potentially diverse genetical identity of the disease in this region.     

Inherited Hemoglobin Disorders in Guinea-Bissau,West Africa: A Population Study

The determination of the prevalence of inherited hemoglobin (Hb) disorders in endemic areas is important in order to develop programs for their control and management. The aim of this study is to determine the prevalence of inherited Hb diseases in Guinea-Bissau which is situated on the west coast of Africa, between Senegal and Guinea. One thousand and fifty-seven blood samples were collected and analyzed with high performance liquid chromatography (HPLC) for detection of β-thalassemia (thal) and Hb variants, and by gap polymerase chain reaction (gap-PCR) for the detection of deletions in the α-globin genes. We found 4.7% children were heterozygous for Hb S [β6(A3)Glu→Val, GAG →GTG], 0.2% were homozygous for Hb S, and 0.3% were heterozygous for Hb C [β6(A3)Glu→Lys, GAG →AAG]. One child had heterozygous β⁺-thal, 13.8% were heterozygous for the ?α^3.7 deletion, 1.5% were homozygous for the ?α^3.7 deletion, and 1.5% were heterozygous for the ?α^4.2 deletion. We recommend national screening programs to focus primarily on sickle cell disease, since β-thal is rare, and the observed α-thal deletions are of minor genetic importance.     

Gγ −37 (A→T): A New Nondeletional Hereditary Persistence of Fetal Hemoglobin Determinant Associated with the Rare Codon 91 (+T) δ0-Thalassemia

We recently described a rare frameshift mutation in the δ-globin gene in a Dutch patient, in association with a new mutation of the ^Gγ-globin gene promoter [^Gγ ?37 (A→T)] with a moderately elevated Hb F level of 2.3%. The δ mutation at codon 91 (+T) has been described once before in our laboratory in 1989, in a complex Belgian family with ^Gγ (^Aγδβ)⁰-thalassemia (thal) and moderately elevated Hb F levels, without the ^Gγ (^Aγδβ)⁰-thal deletion in some individuals. Analysis of the patients from 1989 revealed the presence of the same ^Gγ-globin gene mutation and moderately elevated Hb F in all patients, who were also carriers of the δ-globin gene frameshift. Further analysis demonstrated that the two mutations were in linkage with the same haplotype in both the Belgian family and the recently found patient, confirming the association of the elevated Hb F expression with the new ^Gγ-globin gene mutation.     

Complex Interaction of Hb E [β26(B8)Glu→Lys], Hb Korle-Bu [β73(E17)Asp→Asn] and a Deletional α-thalassemia-1 in Pregnancy

A pregnant Thai woman with mild hypochromic microcytic anemia caused by α- and β- globin defects is described. The proband was a 26-year-old pregnant woman discovered through our ongoing thalassemia screening program. Initial hemoglobin (Hb) high performance liquid chromatography (HPLC) analysis revealed a homozygosity for an unknown variant at the D window, inconsistent with results of family analyses. Further Hb analysis using automated capillary zone electrophoresis identified that the proband was in fact a compound heterozygote for Hb E [β26(B8)Glu→Lys, GAG>AAG] and another β chain variant. DNA analysis demonstrated that she carried the Hb Korle-Bu mutation [β73(E17)Asp→Asn (GAT>AAT)] in trans to the Hb E and an α-thalassemia-1 (α-thal-1) with the Southeast Asian (? ?^SEA) deletion. Family studies identified that her father and sister were double heterozygotes for Hb Korle-Bu and α-thal-1, whereas her mother was a double heterozygote for Hb E/Hb Constant Spring [Hb CS; α142, Term→Gln (TAA>CAA in α2)]. The genotype-phenotype relationship observed in this Thai family with complex hemoglobinopathies and methods for characterization are presented.     

Hb Barika [α42(C7)Tyr→His (α2)] Leads to an α+-Thalassemia-like Syndrome

In human deoxyhemoglobin (deoxyHb), the hydrogen bond between Aspβ99(G1) and Tyrα42(C7), located in the α1β2 interface, is crucial for the stability of the T structure. All the variants that could arise from a single point mutation affecting codon β99 have already been observed, leading always to erythrocytosis. Conversely, up to now, Hb Barika is the only example found in a patient in whom the α42 is mutated. From a biochemical point of view, for theoretical reasons, this substitution has already been extensively studied on recombinant hemoglobin (rHb). In the patient, Hb Barika is expressed at a level lower than expected for an α2 gene variant and leads to an α⁺-thalassemic-like syndrome.     

Hb J-CAPE TOWN [α92(FG4)Arg→Gln (α1), CGG→CAG] in Southern Italy Found in a Patient with Erythrocytosis

A high oxygen affinity hemoglobin (Hb) variant, Hb J-Cape Town [α92(FG4)Arg→Gln (α1), CGG→CAG] was identified in a 30-year-old woman patient from Cosenza (Southern Italy) who had previously been diagnosed with juvenile polycythemia in other hospitals. The occurrence of the variant Hb was assessed by both cation exchange chromatography and liquid chromatography-mass spectrometry (LC-MS) analyses. A detailed structural and functional characterization of the variant was performed at both the protein and DNA level. Structural investigation of the Hb variant by mass spectrometric methodologies and peptide sequencing identified the amino acid replacement as Arg→Gln at α92. The corresponding DNA mutation CGG→CAG was assigned to codon 92 of the α1 gene by DNA sequencing. These findings highlight the importance of investigating the hypothesis of a high affinity variant in the presence of a polycythemia so as to avoid unnecessary bone marrow examination or radioactive treatment. This report represents the first observation of the Hb J-Cape Town variant in Italy.     

Hb Marineo [β70(E14)Ala→Val]: A Silent Hemoglobin Variant with a Mutation Within the Heme Pocket

We report a new hemoglobin (Hb) variant, Hb Marineo [β70(E14)Ala → Val], found in three generations of a family from West Sicily. The mutation is due to a GCC → GTC substitution at codon 70 of the β-globin gene. To date, three mutations at codon 70 of the β-globin gene have been described, presenting with hemolytic anemia. In our case, no anemia or other alteration of hematological indices were found. Cation exchange high performance liquid chromatography (HPLC) showed a peak in the P2 window (VARIANT I), while a peak was detected by VARIANT II HPLC in the P3 window. Reversed phase HPLC analysis showed an abnormal chain amounting to about 40% of the total β chains.