title: DNA polymorphism in the beta-globin gene cluster in Saudi Arabs: relation to severity of sickle cell anaemia.
abstract: Significant DNA polymorphisms have been reported in the beta-globin gene cluster of epsilon-G gamma-A gamma-psi beta-delta-beta-gene region, in normal (Hb AA) individuals and in patients with sickle cell anaemia (SCA). Investigations of the extent of the DNA polymorphisms in the beta A- and beta S-globin gene cluster using Hind III, Hinc II, Ava II, Xmn I, and Hpa I, revealed several associations with mild SCA. The correlation of the presence (+) or absence (-) of the restriction endonuclease site to clinical severity in patients homozygous for beta S-gene showed that the mild form of SCA was associated mainly (> 90%) with the Xmn I polymorphic site 5' to G gamma, and to a lesser extent with Hinc II polymorphic site 5' to epsilon and in the psi beta-gene, with Hind III polymorphic site in G gamma and Hpa I polymorphic site 3' to the beta-globin gene, while in the severe form of SCA these polymorphic sites were absent in most patients. The polymorphism in the beta-globin gene cluster was significantly related to the expression of the beta S-gene and clinical severity of SCA.
mesh_terms: D000755:Anemia, Sickle Cell / Q000097:blood / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D015247:Deoxyribonuclease HindIII; D015252:Deoxyribonucleases, Type II Site-Specific; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis; D005914:Globins / Q000235:genetics*; D006443:Hemoglobin A2 / Q000032:analysis; D006801:Humans; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D012529:Saudi Arabia
chemical_list: D005914:Globins; D004247:DNA; D006443:Hemoglobin A2; D005319:Fetal Hemoglobin; D015247:Deoxyribonuclease HindIII; C024406:endodeoxyribonuclease HpaI; C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific; C038308:GGWCC-specific type II deoxyribonucleases; C024400:GTYRAC-specific type II deoxyribonucleases