[Current views of thalassemia intermedia].
Recently the molecular bases of thalassemia intermedia have been elucidated in several populations. In general this attenuated, non-transfusion dependent form of homozygous beta-thalassemia is mainly determined by a) the co-inheritance of deletion alpha-thalassemia; b) the presence of the so-called mild beta-thalassemia mutations; and more rarely, c) the inheritance of genetic conditions able to enhance the gamma-globin chain expression in adult life. Although there are several complex genetic and acquired interactions involved in the wide clinical heterogeneity of thalassemia intermedia, data in Italians indicate a definite genotype-phenotype relationship in conditions such as the co-inheritance of at least two alpha-thalassemia genes in severe and mild homozygous beta-thalassemia; the molecular homozygosity or double heterozygosity for the -87, -101 and IVS1(nt6) beta(+)-thalassemia mutations; and the coexistence of structural gamma-globin gene defects, i.e. Sicilian and Sardinian delta beta-thalassemias, deletional and non-deletional hereditary persistence of fetal hemoglobin and the polymorphism for the -158 XmnI G gamma restriction site. Thalassemia intermedia resulting from the inheritance in heterozygous beta-thalassemia of triple alpha-globin gene complex or the presence of dominant beta-thalassemia is also described and the role of these new informations in genetic counselling is discussed.
Longinotti
M
M
Istituto di Ematologia e di Endocrinologia, Università, Sassari.
Dore
F
F
Oggiano
L
L
Pardini
S
S
Pistidda
P
P
Guiso
L
L
Frogheri
L
L
Bonfigli
S
S
Murineddu
M
M
Rimini
E
E
D001483:Base Sequence; D006455:Hemoglobins, Abnormal / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007558:Italy; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D013789:Thalassemia / Q000097:blood / Q000175:diagnosis* / Q000235:genetics
D006455:Hemoglobins, Abnormal
Vedute attuali sulla talassemia intermedia.