[Screening for alpha-thalassemia using DNA analysis].
alpha-thalassemia was sought by gene mapping in 258 subjects selected on the basis of origin (25%), microcytosis (7%), or origin and microcytosis combined (64%). Abnormal fragments (Xba I/probe alpha) were found in 58 cases (22.5%). Using other restriction enzymes it was possible to determine the genotype alpha-/aa in 39 patients and the genotype alpha-/alpha- in 13 patients; 2 patients also exhibited hemoglobin H (alpha-/--) disease. alpha triplication anti-3.7 kb was found in 2 subjects and zeta-thalassemia in 2 other samples. 57 out of 58 patients originated from the thalassemia belt or from Africa. alpha-thalassemia is the most frequent hemoglobinopathy (21% of patients at risk) and hematologically is characterized by microcytosis. The Hb A2 level is decreased only in the alpha-/-- form of the disease. The main advantage of diagnosing zeta-thalassemias and alpha triplications lies in the possible clinical implications in the event of association with other hemoglobinopathies or beta-thalassemia.
Beris
P
P
Département de médecine, Hôpital cantonal universitaire de Genève.
Grossiord
D
D
Hochmann
A
A
Zhu
L
L
Miescher
P A
PA
D003937:Diagnosis, Differential; D005260:Female; D005838:Genotype; D006443:Hemoglobin A2 / Q000032:analysis; D006447:Hemoglobin H / Q000032:analysis; D006453:Hemoglobinopathies / Q000175:diagnosis; D006801:Humans; D008297:Male; D015183:Restriction Mapping; D013789:Thalassemia / Q000175:diagnosis / Q000235:genetics*
D006443:Hemoglobin A2; D006447:Hemoglobin H
Dépistage de l'alpha-thalassémie par analyse du DNA.