Evaluation of Thalassemia Mutations in Cases with Normal and Borderline Hemoglobin A2 Values in Premarital Screen Clinic and Thalassemia Center in Sulaymaniyah /Iraq

Parwin Ismael  Haydar; Sana Dlawar  Jalal; Nawsherwan Sadiq  Mohammad

doi:10.56056/

Authors

Parwin Ismael Haydar MBChB, HDH, KHCMS Hematopathology, Hiwa Hospital, Hematopathology Department, Sulaymaniyah, Iraq
Sana Dlawar Jalal MBChB, FRCPath- Haematology-UK, Professor at the University of Sulaymaniyah, College of Medicine, Pathology and Forensic Pathology department, Sulaymaniyah, Iraq.
Nawsherwan Sadiq Mohammad MBChB, FIBMS (Hematopathology), Assistant Professor at the University of Hawler, College of Medicine, Anatomy and Pathology department, Hawler, Iraq. E-mail: [email protected]. Corresponding author: Parwin Ismael Haydar.

DOI:

https://doi.org/10.56056/

Keywords:

Borderline Hb A2, Globin gene defects, Normal HbA2 beta, Thalassemia screening

Abstract

Background and Objectives Elevated hemoglobin A2 level is a diagnostic marker for β-thalassemia carrier screening. However, a small fraction of thalassemia carriers is difficult to diagnose based on Hb A2 levels alone. Here, we described the frequency with molecular and hematological characteristics of a group of thalassemia traits with normal and borderline Hb A2 beta thalassemia to raise awareness on the importance of such cases for haemoglobinopathies screen programs.

Methods: This retrospective study on 4892 cases referred for screening of haemoglobinopathies in Premarital Screen Clinic and Thalassemia Center in Sulaymaniyah province, over the period from December 2009 to October 2023. Hematological parameters were recorded using a standard blood cell counter. Hemoglobin A2 quantification was performed using high-performance liquid chromatography and capillary electrophoresis. Genotypes were detected using Vienna Lab Thalassemia Strip Assays. Negative samples on the above-mentioned methods had been sent for direct sequencing and multiplex ligation-dependent probe amplification.

Results: This study identified 382(7.8%) hemoglobinopathy cases having normal or borderline HbA2 level. Seventy cases with full genotype were included. The age ranged from17-60 years, with male to female ratio of 1.3:1. Of these, 81.4% were thalassemia minor cases, while the result of cases were structural variants. Further, β⁺ and β⁺⁺phenotypes accounted for 80% -thalassemia. Lastly, normal HbA2 was reported in 15.7% of this cohort.

Conclusions: Normal and borderline Hb A2 cases are not uncommon, and a large proportion of them are heterozygous beta thalassemia especially β⁺ thalassemia carriers.

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References

1. Jalal S, Al-Allawi N, Faraj A, Ahmed N. Prevalence of haemoglobinopathies in Sulaymaniyah –Iraq, Dohuk Med J, 2008;2(1): 71–79.

2. Scriver CR, Beaudet AL, Sly WS, Valle D, Stanbury JB, Wyngaarden JB, et al. The Metabolic and Molecular Bases of Inherited Disease, Montreal McGraw-Hill, 2001; 24(1): 45-52.

3. Al-Allawi N, Al-Allawi S, Jalal S. Genetic epidemiology of haemoglobinopathies among Iraqi Kurds, J. Community Genet., 2021; 12: 5–14.

4. Al-Nafie AN, Borgio JF, AbdulAzeez S, Al-Suliman AM, Qaw FS, Naserullah ZA, et al. Co-inheritance of novel ATRX gene mutation and globin (alpha & beta) gene mutations in transfusion dependent beta-thalassemia patients, Blood Cells Mol Dis, 2015; 55: 27-9.

5. Mosca A, Paleari R, Galanello R, Sollaino C, Perseu L, Demartis FR, et al. IFCC Working Group on Standardization of HbA2. New analytical tools and epidemiological data for the identification of HbA2 borderline subjects in the screening for beta-thalassemia. Bioelectrochemistry, 2008; 73: 137-40.

6. Giambona A, Passarello C, Vinciguerra M, Muli RL, Teresi P, Anza M, et al. Significance of borderline hemoglobin A2 values in an Italian population with a high prevalence of beta-thalassemia. Haematol, 2008; 93: 1380-4.

7. Perseu L, Satta S, Moi P, Demartis FR, Manunza L, Sollaino MC, et al. KLF1 gene mutations cause borderline HbA2. Blood, 2011; 118: 4454-8.

8. Borgio JF, AbdulAzeez S, Al-Muslami AM, Naserullah ZA, Al-Jarrash S, Al-Suliman AM, et al. KLF1 gene and borderline hemoglobin A2 in Saudi population, Arch Med Sci, 2018; 14: 230-6.

9. Moradi K, Alibakhshi R, Shafeenia S and Azimi A. Problem of borderline hemoglobin A2 levels in an Iranian population with a high prevalence of α- and β-thalassemia carriers, EJMHG, 2022; 23: 61.

10. Colaco S, Colah R and Nadkarni A. Significance of borderline HbA2 levels in β thalassemia carrier screening, Scientific Reports, 2022; 12: 5414.

11. Hoffbrand AV, Higgs DR, Keeling DM, Mehta AB. Postgraduate Hematology, 7th edn. Blackwell Publishing, Oxford, 2016; 100–103.

12. Tzetis M, Traeger-Synodinos J, Kanavakis E, Metaxotou-Mavromati A & Kattamis C. The molecular basis of normal HbA2 (type 2) beta-thalassaemia in Greece, Hematol Pathol., 1994; 8: 25–34.

13. Gorivale M, Sawant P, Mehta P, Nadkarni A, Ghosh K and Colah R. Challenges in prenatal diagnosis of beta thalassemia: couples with normal HbA2 in one partner. Prenatal Diagnosis, 2015; 35: 1353–1357.

14. Weatherall DJ and Clegg JB. The Thalassemia Syndromes, UK: Blackwell Science Ltd, 2001.

15. Mosca A, Paleari R, Ivaldi G, Galanello R and Giordano PC. The role of haemoglobin A (2) testing in the diagnosis of thalassaemias and related haemoglobinopathies, J Clin Pathol, 2009; 62: 13-17.

16. Luo HY and Chui DHK. Diverse hematological phenotypes of β-thalassemia carriers, Ann N Y Acad Sci, 2016; 1368: 49-55.

17. Lou JW, Li DZ, Zhang Y, He Y, Sun MN, Ye WL, et al. Delineation of the molecular basis of borderline hemoglobin A2 in Chinese individuals, Blood Cells Mol Dis, 2014; 53: 261-4.

18. Denic S, Agarwal MM, Al Dabbagh B, Essa AE, Takala M, Showqi S, et al. Hemoglobin A2 lowered by iron deficiency and alpha thalassemia: should screening recommendation for beta thalassemia change, ISRN Hematol, 2013; 2013: 858294.

19. Paglietti ME, Satta S, Sollaino MC, Barella S, Ventrella A, Desogus MF, et al. The problem of borderline hemoglobin A2 levels in the screening for β-thalassemia carriers in Sardinia, Acta Haematol, 2016; 135: 193-9.

20. Huang J, Zhang X, Liu D, Wei X, Shang X, Xiong F, et al. Compound heterozygosity for KLF1 mutations is associated with microcytic hypochromic anemia and increase fetal hemoglobin, Eur J Hum Genet, 2015; 23: 1341-8.

21. Siatecka M and Bieker JJ. The multifunctional role of EKLF/ KLF1 during erythropoiesis, Blood, 2011; 118: 2044-54. 13.

22. Waye JS and Eng B. Krüppel-like factor 1: hematologic phenotypes associated with KLF1 gene mutations, Int J Lab Hematol, 2015; 37: 78-84.

23. Huisman TH. Levels of Hb A2 in heterozygotes and homozygotes for beta-thalassemia mutations: influence of mutations in the CACCC and ATAAA motifs of the beta-globin gene promoter, Acta Haematol, 1997; 98(4): 187–194.

24. Thein SL. Genetic modifiers of ????-thalassemia, Haematologica, 2005; 90(5): 649–660.

25. Verhovsek M, So CC, shea TO, Gibney GT, Ma ES, Steinberg MH, et al., Is HbA2 level a reliable diagnostic measurement for beta-thalassemia trait in people with iron deficiency, Am. J. Hematol., 2012; 87: 114–116.

26. Steinberg MH and Adams JG. 3rd. Hemoglobin A2: origin, evolution, and aftermath. Blood, 1991; 78: 2165-2177.

27. Galanello R, Barella S, Ideo A, Gasperini D, Rosatelli C, Paderi L, et al. Genotype of subjects with borderline hemoglobin A2 levels Implication for β-thalassemia carrier screening, Am J Hematol, 1994; 46(2):79–81.

28. Gorivale M, Sawant P, Mehta P, Nadkarni A, Ghosh K and Colah R. Challenges in prenatal diagnosis of beta thalassemia: couples with normal HbA2 in one partner, Prenat Diagn, 2015; 35(13):1353–1357.

29. Rangan A, Sharma P, Dadu T, Saxena R, Verma IC, Bhargava M. β-Thalassemia mutations in subjects with borderline HbA2 values: a pilot study in North India, Clin Chem Lab Med, 2011; 49(12):2069–2072.

30. Abdel-Messih IY, Youssef SR, Mokhtar GM, Elmogy MI, Mahmoud HM, Ayoub M, et al. Clinical to molecular screening paradigm for β-thalassemia carriers, Hemoglobin, 2015; 39(4):240–246.

31. Rosnah B, Shahida N, Nazri M, Marini R and Noor HM. The diagnosis of beta thalassemia with borderline HbA2 level among kelantan population, J Blood Disord Transfus, 2017.

32. Old JM. Screening and genetic diagnosis of haemoglobinopathies, Scandinavian Journal of Clinical and Laboratory Investigation, 2007; 67(1): 71–86.

33. Chui D, Fucharoen S, Chan V. Hemoglobin H disease: Not necessarily a benign disorder, Blood, 2003; 101: 791–800.

34. Giambona, A. et al. The significance of the hemoglobin A2 value in screening for hemoglobinopathies, Clin. Biochem, 2009; 42: 1786–1796.

35. Morgado A, Picanco I, Gomes S, Miranda A, Coucelo M, Seuanes F, et al. Mutational spectrum of delta-globin gene in the Portuguese population, Eur. J. Haematol, 2007; 79: 422–428.

36. Phylipsen M, Harteveld CL, Metz MD, Gallivan MV, Arkesteign SG, Luo HY, et al. New and known β-thalassemia determinants masked by known and new δ gene defects Hb A2 Ramallah or δ6[A3] Glu>Gln, GAG> CAG]. Hemoglobin, 2010; 34: 445–450.

37. Rahimi Z, Akramipour R, Nagel RL, Ahmadi AS, Merat A and Bahremand F. The β-globin gene haplotypes associated with Hb D-Los Angeles [β121 (GH4) Glu→ Gln] in western Iran, Hemoglobin, 2006;30(1):39-44.

38. Galehdari H, Salehi B, Azmoun S, Keikhaei B, Zandian KM and Pedramm M. Comprehensive spectrum of the β-thalassemia mutations in Khuzestan, Southwest Iran, Hemoglobin, 2010; 34(5):461-68.