Molecular Characterization of β-Thalassemia Intermedia in Southeast Iran

Spectrum of β-Thalassemia Mutations in Some Areas of Guangxi Zhuang Autonomous Region of Southern China: A Study on a Pediatric Population Aged 0-15 Years

β-Thalassemia (β-thal), one of the most common form of single-gene inheritable blood diseases in the world, is highly prevalent in southern China, especially in the Guangxi Zhuang Autonomous Region. To update the β-thal mutation spectrum in this region, we performed hematological and genetic analyses on 888 β-thal major (β-TM), β-thal intermedia (β-TI) and β-thal carrier patients, aged 0-15 years old, from different parts of Guangxi Province. We identified 55 genotypes and 18 β-thal mutations. The codons 41/42 (-TTCT) (HBB: c.126_129delCTTT) (43.97%), codon 17 (A>T) (HBB: c.52A>T) (25.43%), -28(A>G) (HBB: c.-78A>G) (8.18%), IVS-II-654 (C>T) (HBB: c.316-197C>T) (7.85%) and codon 26 (G>A) (HBB: c.79G>A) (5.02%) were the five most common, accounting for more than 90.0%. The results of our study are providing an up-to-date β-thal mutation spectrum in the 0-15-year-old pediatric population, which will help genetic counseling and prevention of β-TM in mainland China's most endemic region, Guangxi Zhuang Autonomous Region.

Nationwide carrier detection and molecular characterization of β-thalassemia and hemoglobin E variants in Bangladeshi population

Background

ß-thalassemia is one of the most common inherited blood disorders in the world and a major deterrent to the public health of Bangladesh. The management of thalassemia patients requires lifelong frequent blood transfusion and the available treatment options are unsatisfactory. A national policy on thalassemia prevention is mandatory in Bangladesh. However, precise and up-to-date information on the frequency of ß-thalassemia carriers are missing due to lack of accurate diagnostic approaches, limited access to information and absence of national screening program. This study aims to determine the nationwide carrier frequency of hemoglobin E (HbE) and β- thalassemia and mutation spectrum among the carriers using molecular, hematological and biochemical methods.

Methods

The study enrolled a total of 1877 individuals (60.1% male and 39.9% female) aged between 18 and 35 years. Total sample size and its division-wise breakdown were calculated in proportion to national and division-wise population. Venous blood was collected and subjected to CBC analysis and Hb-electrophoresis for each participant. Serum ferritin was measured to detect coexistence of iron deficiency anemia with thalassemia carrier. DNA-based High Resolution Melting (HRM) curve analysis was performed for confirmation of carrier status by mutation detection.

Results

Of 11.89% (95% CI, 10.43–13.35) carriers of β-globin gene mutations, 8.68% (95% CI, 7.41–9.95) had HbE trait (ETT) and 2.24% (95% CI, 1.57–2.91) had beta-thalassemia trait (BTT). Among eight divisions, Rangpur had the highest carrier frequency of 27.1% (ETT-25%, BTT-2.1%), whereas Khulna had the lowest frequency of 4.2% (ETT-4.2% only). Moreover, α- thalassemia, HbD trait, HbE disease, hereditary persistence of HbF were detected in 0.11, 0.16, 0.43 and 0.16% participants, respectively. HRM could identify two individuals with reported pathogenic mutations in both alleles who were erroneously interpreted as carriers by hematological indices. Finally, a total of nine different mutations including a novel mutation (c.151A > G) were detected in the β-globin gene.

Conclusions

Since carrier frequency for both HbE and β-thalassemia is alarmingly high in Bangladesh, a nationwide awareness and prevention program should be made mandatory to halt the current deteriorating situations. Mutation-based confirmation is highly recommended for the inconclusive cases with conventional carrier screening methods to avoid any faulty detection of thalassemia carriers.

Co-inheritance of alpha globin gene deletion lowering serum iron level in female beta thalassemia patients

In the Eastern province of Saudi Arabia, thalassemia is highly common. Data on the effect of alpha globin gene variation on the concentration of iron on transfusion dependent Saudis are scanty. A total of 166 transfusions dependent β-thalassemia were included in this study to understand association between the alpha globin gene variation and concentration of iron. Using multiplex PCR, the alpha globin gene deletions were identified. Also, HBA1 and HBA2 genes were sequenced by Sanger sequencing. Saudi transfusion dependent female β-thalassemia patients with wild alpha globin genotype (αα/αα) were observed with iron level beyond the normal range. However, normal range of iron was observed in transfusion dependent Saudi female beta thalassemia patients co-inherited with double (-α^3.7/-α^3.7, or --^Fil/αα or --^MED/αα or - (α) ^20.5/αα) or double heterozygosity (- -/-α^3.7) alpha globin gene deletions, which is significantly (p < 0.0001) less compared to the Saudi transfused female with wild alpha globin genotype (αα/αα). The co-inheritance alpha globin gene deletions in female beta thalassemia patients were significantly lowering serum iron. Detailed studies can be taken forward to identify the molecular pathways involved in globin gene deletion as modulator.

Hypothyroidism and Hypoparathyroidism in Thalassemia Major Patients: A Study in Sistan and Baluchestan Province, Iran

BACKGROUND

Hypothyroidism (HT) and hypoparathyroidism (HPT) are common endocrine complications in thalassemia major (TM) patients.

OBJECTIVES

In the present study, we assessed the frequency of HT and HPT in a population of TM patients in Southeast of Iran.

METHODS

This cross sectional study was performed on 194 TM patients in Zabol, Sistan and Baluchestan Province, Iran, during February - July 2016. The demographic, clinical, and laboratory data were collected via interviews and history - taking. For hormone measurements, specific ELISA kits were used. Statistical analysis was performed in SPSS version 16.

RESULTS

A total of 103 (53.1%) and 91 (46.9%) females and males were recruited in this study, respectively. The mean age of the patients was 15 ± 7.5 years. HT and HPT showed overall frequencies of 8.2% (18/194) and 18% (35/194), respectively. Subclinical and overt HT were observed in 13 (6.7%) and 5 (2.6%) patients, respectively. There was no significant association between HT and age, while patients with HPT were significantly older than those without HPT (20.1 ± 5.8 vs. 13.9 ± 6.2 years; P < 0.001). HPT was significantly associated with the mean received blood per transfusion (P = 0.009), total transfused blood per year (P = 0.01), splenomegaly (P < 0.001), splenectomy (P < 0.001), hepatomegaly (P = 0.01), and chelation regimen (P < 0.001). The ferritin level was correlated with neither HT nor HPT. Also, no significant difference was observed between patients with or without HT or HPT regarding the cooccurrence of either diabetes or hepatitis C virus (HCV) infection. In the multivariate analysis, splenectomy remained an independent risk factor for HPT after correction for potential covariates (OR, 6.5; 95% CI, 1 - 39.2; P = 0.04).

CONCLUSIONS

In patients with TM, HT was a complication with a relatively low frequency, while HPT was more common. Based on the findings, HPT was more frequent in older patients receiving regular blood transfusions, thereby necessitating close monitoring of these patients.

The ‑α3.7 deletion in α‑globin genes increases the concentration of fetal hemoglobin and hemoglobin A2 in a Saudi Arabian population

The regions of Al‑Qatif and Al‑Ahssa in the Eastern Province of Saudi Arabia are known for their high prevalence of hemoglobinopathies, including β‑thalassemia and sickle cell anemia. Previously, the α‑gene deletion has been demonstrated as highly prevalent among populations residing in these two regions. The present study was conducted in order to investigate the implications of the α‑globin gene deletion on fetal hemoglobin (HbF) and hemoglobin α2 (HbA2) concentrations in patients with transfusion‑dependent β‑thalassemia. A total of 166 Saudi patients with transfusion‑dependent β‑thalassemia and 337 healthy Saudi patients were included in the study. The ‑α3.7, ‑α4.2, -‑FIL, -‑SEA, -‑MED and -‑(20.5) gene deletions were identified using multiplex α‑globin deletion polymerase chain reaction. The present study revealed that the ‑α3.7 gene deletion is the most prevalent (43.5%) in the Saudi populations that were analyzed and is characterized by the deletion of 3,804 base pairs. Numerous genotypes, namely ‑3.7α2/α1α2, ‑3.7α2/α1α12, ‑3.7α2/‑3.7α2, ‑3.7α2HphI/α1α2HphI, ‑3.7α2/α1‑4.2, ‑3.7α2/α1polyA‑1α2, ‑3.7α12/α1α12, ‑‑FIL/‑3.7α2 and ‑3.7α2/‑3.7α2Hb Villiers le Bel were also identified in the investigated population. Furthermore, a gradual increase in the concentration of HbF and HbA2 in patients with β‑thalassemia and the number of α‑gene deletions was demonstrated; whereas in healthy patients the level of HbA2 was demonstrated to decrease as the number of α‑gene deletions increased. Therefore, it can be concluded that the high HbF concentration in the present study is predominantly associated with other mutations associated with β‑thalassemia rather than α‑globin deletions. Furthermore, the results of the present study also revealed novel α‑gene deletion genotypes prevalent in the population studied, namely α1α2/α1α2HphI, α1α2HphI/α1α2HphI, α1α2/α1α2Hb Handsworth, ‑3.7α2HphI/α1α2HphI, ‑3.7α2/‑3.7α2Hb Villiers le Bel and ‑-MED/α1α2HphI.