ISSN: 1300-7777 E-ISSN: 1308-5263
Compound heterozygosity for two beta chain variants: the mildly unstable Hb Tyne (codon 5 Pro→Ser) and HbS (codon 6 Glu→Val) [Turk J Hematol]
Turk J Hematol. 2005; 22(1): 37-40

Compound heterozygosity for two beta chain variants: the mildly unstable Hb Tyne (codon 5 Pro→Ser) and HbS (codon 6 Glu→Val)

Özlem Güzeloğlu Kayışlı1, İbrahim Keser1, Osman Nidai Özeş1, Duran Canatan2, Akif Yeşilipek3, Güven Lüleci1
1Department Of Medical Genetics, Akdeniz University School Of Medicine, Antalya, Turkey
2Antalya State Hospital, Thalassemia Center, Antalya, Turkey
3Department Of Pediatric Oncology, Akdeniz University School Of Medicine, Antalya, Turkey

Compound heterozygosity for Hb Tyne and HbS, that is very rare, was identified by direct DNA sequencing of the beta-globin gene in a Turkish patient. Hematological investigation of a girl at the age of 9 due to the presence of HbS (40.7%) led to the identification of a compound heterozygosity at codons 5-6. This was found to be the result of substitution of cytosine (C) for thymidine (T) at the fifth position and a substitution of adenine (A) for thymidine (T) at the sixth position of the beta globin gene. As a result of these mutations, the order of amino acids at codons 5-6 was changed from Pro-Glu to Ser-Val, respectively. Since the co-inheritance of Hb Tyne and HbS had not been reported in literature before, our case set an example for identification of coinheritance of Hb Tyne and HbS for the first time. Therefore, such cases may be considered as an important example for understanding the structural variants of hemoglobin and may provide important clues for critical amino acids responsible for stabilization of hemoglobin tetrameric structure and genetic counseling.

Keywords: Hemoglobin S, Hemoglobin Tyne, Beta-globin, Heterozygosity, DNA sequence.


İki beta zincir varyantının birlikteliği: Hb Tyne [codon 5 Pro→Ser] ve HbS [codon 6 Glu→Val]

Özlem Güzeloğlu Kayışlı1, İbrahim Keser1, Osman Nidai Özeş1, Duran Canatan2, Akif Yeşilipek3, Güven Lüleci1
1Department Of Medical Genetics, Akdeniz University School Of Medicine, Antalya, Turkey
2Antalya State Hospital, Thalassemia Center, Antalya, Turkey
3Department Of Pediatric Oncology, Akdeniz University School Of Medicine, Antalya, Turkey

Nadir görülen Hb Tyne ve HbS birlikteliği, hematolojik tetkik sonucu %40.7 HbS bulunan dokuz yaşındaki bir kız çocukta, beta-globin geninin direkt DNA dizi analizi sonucu ile kodon 5 ve kodon 6’da tanımlanmıştır. Bu mutasyonlar beta-globin geninde 5. kodonda sitozin yerine timinin, 6. kodonda adenin yerine timinin yer alması ile Hb Tyne ve HbS varyantları olarak ortaya çıktıkları görüldü. Bu mutasyonların sonucu olarak 5. ve 6. kodonlardaki aminoasitler ise sırasıyla Pro ve Glu yerine Ser ve Val şeklinde değişmişlerdir. Hb Tyne ve HbS’nin birlikte kalıtımı ilk defa bizim olgumuzda gözlenmiş olup, bu bulgu hemoglobinin yapısal varyantlarının, tetrame rik yapısının stabilizasyonu için sorumlu kritik aminoasitlerin öneminin anlaşılmasında ve doğru genetik danışma verilmesinde önemli rol oynayabilir.

Anahtar Kelimeler: Hemoglobin S, Hemoglobin Tyne, Beta-globin, Heterozigosite, DNA dizi analizi.


Özlem Güzeloğlu Kayışlı, İbrahim Keser, Osman Nidai Özeş, Duran Canatan, Akif Yeşilipek, Güven Lüleci. Compound heterozygosity for two beta chain variants: the mildly unstable Hb Tyne (codon 5 Pro→Ser) and HbS (codon 6 Glu→Val). Turk J Hematol. 2005; 22(1): 37-40

Corresponding Author: İbrahim Keser, Türkiye


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