[Molecular diagnosis of beta-thalassemia intermedia].
OBJECTIVE
To analyze the molecular abnormalities of beta-thalassemia intermedia and contribute to the knowledge of the molecular diagnosis and prenatal diagnosis of this disorder.


METHODS
In 14 patients with beta-thalassemia intermedia, we analyzed the hematologies, alpha, beta and gamma globin gene organization and structure as well as globin gene biosynthesis by Southern blot hybridization, multiplex allale specific PCR (MAS-PCR), DNA sequencing and micro-globin chain biosynthetic assay. Moreover, alpha globin gene organization was studied in 250 cord blood specimens.


RESULTS
Of the 14 patients, 4 were found to be beta-thalassemia heterozygotes combined with rightward cross-over or/and leftward cross-over triplicated haplotype of alpha-globin gene loci (alpha alpha alpha anti3.7 or/and alpha alpha alpha anti4.2), 3 were compound heterozygotes for beta-thalassemia combined with alpha-thalassemia 1 or 2, one was identified to be a compound heterozygote for beta-thalassemia combined with G gamma promotor-158 (C-->T) mutation. The data of the alpha globin gene organization in 250 cord blood specimens showed that 8 of the 500 tested chromosomes (1.6%) were abnormal: 3 were alpha alpha alpha anti3.7, 4 were alpha -3.7, and one was --SEA.


CONCLUSIONS
In addition to beta-thalassemia homozygote or compound heterozygotes with alpha thalassemia, the conjunctive abnormalities of beta-thalassemia heterozygote with alpha-globin gene triplication was another major cause of beta-thalassemia intermedia.
Shanghai Institute of Medical Genetics, Shanghai Children's Hospital.
J
J
Chen
W
W
Liu
M
M
Chen
D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D005312:Fetal Blood; D005914:Globins / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D017422:Sequence Analysis, DNA; D017086:beta-Thalassemia / Q000175:diagnosis / Q000235:genetics*
D005914:Globins