title: Identification of a nondeletion defect in alpha-thalassemia.
abstract: The molecular defect that has been demonstrated in alpha-thalassemia is the deletion of the alpha-globin structural genes. Since thalassemias are composed of heterogeneous groups of disorders, other types of defects could also result in alpha-thalassemia. We studied a Chinese family in which analysis of the mode of inheritance of alpha-thalassemia-1 and hemoglobin-H disease suggests a lesion that is not due to structural-gene deletion. Molecular hybridization studies with synthetic radioactive DNA's complementary to alpha-globin mRNA sequences show that in addition to the usual deletion defect, a nondeletion defect produces the phenotype of alpha-thalassemia-1. The combination of the deletion and non-deletion defects results in hemoglobin-H disease and not homozygous alpha-thalassemia associated with hydrops fetalis.
mesh_terms: D002872:Chromosome Deletion; D005260:Female; D005796:Genes; D005914:Globins / Q000096:biosynthesis; D006447:Hemoglobin H; D006455:Hemoglobins, Abnormal; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization; D010375:Pedigree; D010641:Phenotype; D012333:RNA, Messenger; D013789:Thalassemia / Q000097:blood / Q000235:genetics*
chemical_list: D006455:Hemoglobins, Abnormal; D012333:RNA, Messenger; D005914:Globins; D006447:Hemoglobin H