delta-Thalassemic phenotype due to two "novel" delta-globin gene mutations: CD11[GTC-->GGC (A8)-HbA2-Pylos] and CD 85[TTT-->TCT(F1)-HbA2-Etolia].
delta-Thalassemia reduces the expected HbA2 percentage, altering the normal as well as the beta-thalassemia trait phenotype. An attempt to elucidate the molecular basis of delta-thalassemia in the Greek population, revealed two cases with unknown molecular defects that presented low levels of HbA2 (about 1.5%). DNA sequence analysis of delta-globin gene identified two "novel" mutations in the coding regions of the gene; the cd11 (GTC-->GGC) resulting in the substitution of valine for glycine (:HbA2-Pylos) and the cd85(TTT-->TCT) resulting in the substitution of phenylalanine for serine (:HbA2-Etolia). Because these mutations are localized at the helical positions A8 and F1 of the HbA2 respectively, they potentially cause molecular instability of the tetramer, thus leading to reduced HbA2 percentage.
Drakoulakou
O
O
Laikon General Hospital, Center for Thalassemias, Athens, Greece.
Papapanagiotou
E
E
Loutradi-Anagnostou
A
A
Papadakis
M
M
D000328:Adult; D004252:DNA Mutational Analysis; D005796:Genes / Q000235:genetics; D005914:Globins / Q000235:genetics; D006115:Greece; D006443:Hemoglobin A2 / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics*; D013789:Thalassemia / Q000235:genetics*
D006455:Hemoglobins, Abnormal; C106312:hemoglobin A2 Etolia; C106313:hemoglobin A2 Pylos; D005914:Globins; D006443:Hemoglobin A2