Molecular characterization of β-thalassemia intermedia: a report from Iran.
Thalassemia intermedia is a clinical definition applied to patients whose clinical phenotype is milder than thalassemia major. To characterize different common mechanisms involving in pathogenesis of moderate to severe β-thalassemia intermedia, we have studied four factors in 38 Iranian patients with thalassemia intermedia: β-globin gene mutation, deletion in α-globin genes, presence of XmnI polymprphism and RFLP haplotype at β-globin gene cluster. The results showed that 84.4% of patients were associated with severe mutations in β-globin gene, mainly IVSII-1(G to A) (56.4%). The positive XmnI polymorphism was seen in 76.9% of the studied alleles which showed strong linkage to β° mutations and high level of fetal hemoglobin. Co-existence of α-globin gene deletions, β(+) mutation and the most frequent of RFLP haplotype (-/-, +/+, -/+, +/+, +/+, +/+, -/-) were seen in 7.7, 12.8 and 17.9%, respectively. In this group of our study it seems the main ameliorating factor in the patients was co-inheritance of a positive XmnI polymorphism with β° mutation especially IVSII-1, which were associated with increased production of fetal hemoglobin. However, the other probable genetic factors should be investigated to describe genotype-phenotype correlation in thalassemia intermedia patients.
Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur Street, 13164 Tehran, Iran.
Aida
A
Arab
Morteza
M
Karimipoor
Ali
A
Rajabi
Mohammad
M
Hamid
Sedeigheh
S
Arjmandi
Sirous
S
Zeinali
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007492:Iran; D005810:Multigene Family / Q000235:genetics; D055815:Young Adult; D055542:alpha-Globins / Q000235:genetics; D055544:beta-Globins / Q000235:genetics; D017086:beta-Thalassemia / Q000235:genetics*
D055542:alpha-Globins; D055544:beta-Globins; C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific