The simultaneous presence of alpha- and beta-thalassaemia alleles: a pitfall of thalassaemia screening.
OBJECTIVE
To compare the efficacy of routine haematological tests and molecular analysis in the diagnosis of double heterozygous alpha- and beta-thalassaemia.


METHODS
Screening was carried out in extended family members from 125 families registered in the National Thalassaemia Registry, known to have both alpha- and beta-thalassaemia carriers.


RESULTS
Eighty-three individuals from 59 families were identified to be double heterozygous for alpha- and beta-thalassaemia only upon molecular analyses. Among 40 married individuals, 1 was at 25% risk for having beta-thalassaemia major children and 6 for having Bart's hydrops pregnancies.


CONCLUSIONS
Molecular analysis must be used for the accurate diagnosis of double heterozygous alpha- and beta-thalassaemia for proper risk ascertainment, especially in regions with a high prevalence of both types of thalassaemia.
Law
H Y
HY
Genetics Service, Department of Paediatric Medicine, KK Women's & Children's Hospital, 100 Bukit Timah Road, 229 899 Singapore.
Chee
M K L
MK
Tan
G P
GP
Ng
I S L
IS
D000483:Alleles; D005190:Family; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D017085:alpha-Thalassemia / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D017086:beta-Thalassemia / Q000150:complications / Q000175:diagnosis* / Q000235:genetics