Heteroduplex detection: application to rapid prenatal diagnosis for a type of beta-thalassaemia most commonly found in south China

Carrier screening for alpha- and beta-thalassemia in pregnancy: the results of an 11-year prospective program in Guangzhou Maternal and Neonatal hospital

OBJECTIVES

To evaluate the first prospective screening program in China for control of alpha and beta-thalassemia in the population of pregnant couples.

METHODS

During the period between January 1993 and December 2003, a hospital-based preventive program was conducted at the biggest birth center in Guangzhou, with 1/17 of all deliveries in this city referred annually by use of conventional heterozygote screening strategy in combination with the system of regular healthcare examination in pregnancy.

RESULTS

The screened records included 49 221 pregnant women, and 4503 husbands of the pregnant women showed positive on the screening test. Of the at-risk couples, there were 198 for alpha-thal (4.4%) and 83 for beta-thal (1.8%), respectively. Genetic counseling was offered to all at-risk couples and a successful prenatal diagnosis was performed for 269 out of 281 (95.7%) for alpha- or beta-thal major, with the remaining 12 couples refusing to accept prenatal diagnosis. Out of 187 pregnancies at risk for homozygous alpha0-thal and 82 at risk for beta-thal major, 51 hydrops fetalis with Hb Bart's and 18 beta-thal major were identified. All pregnancies with affected fetuses were voluntarily terminated, leading to a marked reduction of severe alpha- and beta-thal births at this hospital since the program has been launched.

CONCLUSIONS

Our hospital-based program proved to be highly effective in reducing severe thals in pregnant populations.