β-Globin chain abnormalities with coexisting α-thalassemia mutations.
BACKGROUND
The frequency of hemoglobinopathies is still high in Adana, the biggest city of the Cukurova Region that is located in the southern part of Turkey. Our aim was to identify the concomitant mutations in α- and β-globin genes which lead to complex hemoglobinopathies and to establish an appropriate plan of action for each subject, particularly when prenatal diagnosis is necessary.


METHODS
We studied the association between the β-globin gene and α-thalassemia genotypes. The reverse hybridization technique was employed to perform molecular analysis, and the results were confirmed by amplification refractory mutation system (ARMS) or restriction fragment length polymorphism (RFLP) technique.


RESULTS
We evaluated 36 adult subjects (28 female and 8 male; age range: 18-52 years) with concomitant mutations in their α- and β-globin genes. The -α(3.7)/αα deletion was the commonest defect in the α-chain as expected, followed by α(3.7)/-α(3.7) deletion. Twenty-five of 36 cases were sickle cell trait with coexisting α-thalassemia, while seven Hb S/S patients had concurrent mutations in their α-genes. The coexistence of α(PolyA-2)α/αα with Hb A/D and with Hb S/D, which is very uncommon, was also detected. There was a subject with compound heterozygosity for β-globin chain (-α(3.7)/αα with IVSI.110/S), and also a case who had -α(3.7)/αα deletion with IVSI.110/A.


CONCLUSIONS
Although limited, our data suggest that it would be valuable to study coexisting α-globin mutations in subjects with sickle cell disease or β-thalassemia trait during the screening programs for premarital couples, especially in populations with a high frequency of hemoglobinopathies.
Department of Hematology, Faculty of Medicine, Cukurova University, Adana, Turkey ; Hemapheresis, Stem Cell and Cryopreservation Unit, Cukurova University, Balcali Hospital, Adana, Turkey ; Seyhan Hereditary Blood Disorders Center, Adana, Turkey.
Birol
B
Guvenc
Abdullah
A
Canataroglu
Cagatay
C
Unsal
Sule Menziletoglu
SM
Yildiz
Ferda Tekin
FT
Turhan
Sevcan Tug
ST
Bozdogan
Suleyman
S
Dincer
Hakan
H
Erkman