Spectrum of Beta Globin Gene Mutations in Egyptian Children with β-Thalassemia

Mr El-Shanshory, Aa Hagag, Ss Shebl, Im Badria, Ah Abd Elhameed, Es Abd El-Bar, Y Al-Tonbary, A Mansour, H Hassab, M Hamdy, M Alfy, L Sherief, E Sharaf, Mr El-Shanshory, Aa Hagag, Ss Shebl, Im Badria, Ah Abd Elhameed, Es Abd El-Bar, Y Al-Tonbary, A Mansour, H Hassab, M Hamdy, M Alfy, L Sherief, E Sharaf

Abstract

Background: The molecular defects resulting in a β-thalassemia phenotype, in the Egyptian population, show a clear heterogenic mutations pattern. PCR-based techniques, including direct DNA sequencing are effective on the molecular detection and characterization of these mutations. The molecular characterization of β-thalassemia is necessary for carrier screening, genetic counseling, and to offer prenatal diagnosis.

The aim of the work: was to evaluate the different β-globin gene mutations in two hundred β-thalassemic Egyptian children.

Subjects and methods: This study was carried out on two hundred β-thalassemic Egyptian children covering most Egyptian Governorates including 158 (79%) children with thalassemia major (TM) and 42 (21%) children with thalassemia intermedia(TI). All patients were subjected to meticulous history taking, clinical examination, complete blood count, hemoglobin electrophoresis, serum ferritin and direct fluorescent DNA sequencing of the β-globin gene to detect the frequency of different mutations.

Results: The most common mutations among patients were IVS I-110(G>A) 48%, IVS I-6(T>C) 40%, IVS I-1(G>A) 24%, IVS I-5(G>C)10%, IVS II-848 (C>A) 9%, IVS II-745(C>G) 8%, IVS II-1(G>A) 7%, codon "Cd"39(C> T) 4%, -87(C>G) 3% and the rare mutations were: Cd37 (G>A), Cd8 (-AA), Cd29(-G), Cd5 (-CT), Cd6(-A), Cd8/9(+G), Cd 106/107(+G), Cd27(C>T), IVS II-16(G> C), Cd 28 (-C), Cap+1(A>C), -88(C>A), all of these rare mutations were present in 1%. There was a considerable variation in phenotypic severity among patients resulting from the interaction of different β(∘) and β+mutations. Furthermore, no genotype-phenotype association was found both among the cases with thalassemia major and the cases with thalassemia intermedia.

Conclusion: Direct DNA sequencing provides insights for the frequency of different mutations in patients with β-thalassemia including rare and/or unknown ones. The most common mutations in Egyptian children with beta thalassemia were IVS I-110(G>A) 48%, IVS I-6(T>C) 40%, IVS I-1(G>A)24%, IVS I-5(G>C)10%, IVS II-848 (C>A) 9%, IVS II-745(C>G) 8%, IVS II-1(G>A) 7%.

Figures

Figure 1
Figure 1
Map showing geographic distribution of different governorates in Egypt
Figure 2
Figure 2
Examples of SeqScape elctropherograms.

References

    1. Flint J, Harding RM, Boyce AJ, Clegg JB. The population genetics of hemoglobinopathies. Baillières clinical hematology. 1993;6(1):215–262. doi: 10.1016/S0950-3536(05)80071-X.
    1. Weatherall DJ, Clegg JB. Inherited haemoglobin disorders: an Increasing global health problem. Bulletin of the World Health Organization. 2001;79:704–712.
    1. Patrinos GP, Giardine B, Riemer C, Miller W, Chui DHK, Anagnou NP, Wajcman H, Hardison RC. Improvements in the HbVar database of human hemoglobin variants and thalassemia mutations for population and sequence variation studies. Nucl. Acids Res. 2004;32(Database issue):D537–541. .
    1. El-Beshlawy A, Kaddah N, Ragab L, Hussein I, Mouktar G, Moustafa A, El-Raouf E, Hassaballa N, Gaafarand T, El-Sendiony H. Thalassemic prevalence and status in Egypt. Proceedings of the annual meeting of the American Pediatric Society; San Francisco, CA, USA. 1–4 may 1999; abstract 102.
    1. El-Hashemite N, Petrou M, Khalifa AS, Heshmat NM, Rady MS, Delhanty JD. Identification of novel Asian Indian and Japanese mutations causing β-thalassemia in Egyptian population. Hum Genet. 1997;99(2):271–274. doi: 10.1007/s004390050352.
    1. Borgna-Pignatti C, Rugolotto S, De Stefano P, Piga A, Di Gregorio F, Gamberini MR, Sabato V, Melevendi C, Cappellini MD, Verlato G. Survival and disease complications in thalassemia major. Ann NY Acad Sci. 1998;85:227–231. doi: 10.1111/j.1749-6632.1998.tb10479.x.
    1. Caro JJ, Ward A, Green TC, Huybrechts K, Arana A, Wait S, Eleftheriou A. Impact of thalassemia major on patients and their families. Acta Haematol. 2002;107(3):150–157. doi: 10.1159/000057633.
    1. Sanger F, Nicklen S, Coulson AR. DNA sequencing with chain terminating inhibitors. Proc Nat Acad Sci USA. 1997;74:5463–5467. doi: 10.1073/pnas.74.12.5463.
    1. Henikoff Steven. Unidirectional digestion with exonuclease III creates targeted breakpoints for DNA sequencing. Gene. June;1984;28(3):351–359.
    1. Nadkarni AA, Gorakshakar A, Colah R, Mohanty D, Ghosh K. Evaluation of the clinical severity of β thalassemia homozygous patients using a phenotypic scoring system. Journal of Chinese Clinical Medicine. 2007;2(8):439–447.
    1. El-Beshlawy A, Youssry I. Prevention of hemoglobinopathies in Egypt. Hemoglobin. 2009;33(1):14–20. doi: 10.3109/03630260903346395.
    1. Christopoulos G, Ezzat GM, Kleanthous M. Use of denaturing gradient gel electrophoresis in screening unknown β-thalassemia mutations in Egyptian patients. The Egyptian Journal of Medical Human Genetics. 2012;13:343–349. doi: 10.1016/j.ejmhg.2012.06.008.
    1. Hussein G, Fawzy M, Serafi TE, Ismail EF, Metwally DE, Saber MA, Giansily M, Schved JF, Pissard S, Martinez PA. Rapid detection of β-thalassemias in Egypt using naturally or amplified created restriction sites and direct sequencing: a step in disease control. Hemoglobin. 2007;31(1):49–62. doi: 10.1080/03630260601057088.
    1. Kaddah N, Rizk S, Kaddah AM, Salama K, Lotfy H. Study of possible genetic factors determining the clinical picture of Thalassemia Intermedia. J Med Sci. 2009;9:151–155. doi: 10.3923/jms.2009.151.155.
    1. Settin AA, Al-Haggar MM, Neamatallah M, Al-Said AM, Hafez MM. Detection of beta-thalassaemia mutations using primer-specific amplification compared to reversed dot blot hybridization technique in Egyptian cases. Haema. 2006;9(3):401–409.
    1. Jiffri EH, Bogari N, Zidan KH, Teama S, Elhawary NA. Molecular updating of β-thalassemia mutations in the upper Egyptian population. Hemoglobin. 2010;34(6):538–547. doi: 10.3109/03630269.2010.526440.
    1. Omar A, Abdel Karim E, El Gendy W, Marzouk I, Wagdy M. Molecular basis of beta thalassemia in Egypt. Egypt J Immunol. 2005;12(1):15–24.
    1. El-Gawhary S, El-Shafie S, Niazi M, Aziz M, El-Beshlawy A. Study of β-thalassemia mutations using the polymerase chain reaction-amplification refractory mutation system and direct DNA sequencing techniques in a group of Egyptian thalassemia patients. Hemoglobin. 2007;31(1):63–69. doi: 10.1080/03630260601057104.
    1. Novelletto A, Hafez M, Deidda G, et al. Molecular analysis of β-thalassemia in the Mediterranean coast and Nile delta region of Egypt. Proceedings of the 1st Egyptian Italian Symposium on Biotechnology; Assiut, Egypt. 1992. pp. 21–23.

Source: PubMed

Sponzoři a spolupracovníci

Zdravotní podmínky

Drogové intervence

3
Předplatit