β-Globin Genes: Mutation Hot-Spots in the Global Thalassemia Belt

Increased Expression of α-Hemoglobin Stabilizing Protein (AHSP) mRNA in Erythroid Precursor Cells Isolated from β-Thalassemia Patients Treated with Sirolimus (Rapamycin)

Background/Objectives: in β-thalassemia, important clinical complications are caused by the presence of free α-globin chains in the erythroid cells of β-thalassemia patients. These free α-globin chains are present in excess as a result of the lack of β-globin chains to bind with; they tend to aggregate and precipitate, causing deleterious effects and overall cytotoxicity, maturation arrest of the erythroid cells and, ultimately, ineffective erythropoiesis. The chaperone protein α-hemoglobin-stabilizing protein (AHSP) reversibly binds with free α-globin; the resulting AHSP-αHb complex prevents aggregation and precipitation. Sirolimus (rapamycin) has been previously demonstrated to induce expression of fetal hemoglobin and decrease the excess of free α-globin chain in the erythroid cells of β-thalassemia patients. The objective of this study was to verify whether sirolimus is also able to upregulate AHSP expression in erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. Methods: the expression of AHSP genes was analyzed by measuring the AHSP mRNA content by real-time quantitative PCR (RT-qPCR) and the AHSP protein production by Western blotting. Results: AHSP gene expression was found to be higher in ErPCs of β-thalassemia patients in comparison to ErPCs isolated from healthy subjects. In addition, AHSP expression was further induced by treatment of β-thalassemia ErPCs with sirolimus. Finally, AHSP mRNA was expressed at an increased level in ErPCs of sirolimus-treated β-thalassemia patients participating in the NCT03877809 Sirthalaclin clinical trial. Conclusions: this exploratory study suggests that AHSP expression should be considered as an endpoint in clinical trials based on sirolimus.

Knowledge and Attitude toward Hemoglobinopathies in Premarital Screening Program among the General Population in the Western Region of Saudi Arabia

The National Premarital Screening Program, which includes sickle cell disease and thalassemia, was made mandatory in 2004 by the Kingdom of Saudi Arabia (KSA), and the earlier studies have shown a poor knowledge and negative attitude toward this program in the different study groups. This study was conducted to assess the knowledge and attitudes toward premarital screening (PMS) in a randomly selected national sample of the Saudi population, 18 years and above. This was a cross-sectional study conducted in the Saudi population in the western region between July and December 2021. Valid and reliable questionnaire and data were collected from 893 participants aged ≥18 years. The χ² test was used to ascertain if there is an association between categorical variables. Multivariate logistic regression was used to determine factors predicting satisfactory knowledge. All 893 study participants had heard about PMS with 625 (70.0%), 244 (27.3%) and 24 (2.7%) having satisfactory, fair and poor knowledge, respectively. Participants aged 26-35 years (p =0 .038), females (p < 0.001), those with higher education (p = 0.003) and employed (p = 0.004), had a better knowledge compared to other groups. Most of the participants had a positive attitude toward PMS. There is a changing trend in the knowledge and attitude toward PMS with a greater number of people wanting to go for PMS. There is also an improvement in the number of participants opting out of marriage in case of incompatibility with their future partner. However, the health education programs need to be improved regarding the hemoglobinopathies.

Analysis of rare thalassemia genetic variants based on third-generation sequencing

Thalassemia is a group of common hereditary anemias that cause significant morbidity and mortality worldwide. However, precisely diagnosing thalassemia, especially rare thalassemia variants, is still challenging. Long-range PCR and long-molecule sequencing on the PacBio Sequel II platform utilized in this study could cover the entire HBA1, HBA2 and HBB genes, enabling the diagnosis of most of the common and rare types of thalassemia variants. In this study, 100 cases of suspected thalassemia were subjected to traditional thalassemia testing and third-generation sequencing for thalassemia genetic diagnosis. Compared with traditional diagnostic methods, an additional 10 cases of rare clinically significant variants, including 3 cases of structure variants and 7 cases of single nucleotide variations (SNVs) were identified, of which a case with − α^3.7 subtype III (− α^3.7III) was first identified and validated in the Chinese population. Other rare variants of 11.1 kb deletions (− 11.1/αα), triplicate α-globin genes (aaa^3.7/αα) and rare SNVs have also been thoroughly detected. The results showed that rare thalassemia variants are not rare but have been misdiagnosed by conventional methods. The results further validated third-generation sequencing as a promising method for rare thalassemia genetic testing.