Pre Gestational Thalassemia Screening in Mainland China: The First Two Years of a Preventive Program

Abstract

In this study, we report the experience of a pre gestational thalassemia screening program at a single center in Southern China. Free thalassemia screening, genetic counseling and prenatal diagnosis (PND) for couples planning pregnancy were implemented over a 2-year period. Among a total of 83,062 screened individuals (41,531 couples), the allele frequencies of β-thalassemia (β-thal), - - and - - deletions were 3.79, 5.75 and 0.028%, respectively. Out of the 41,531 couples, 11,039 couples had at least one partner who had a positive screening test; of these, 455 at-risk couples (1.07%) were identified, including 68 (0.16%) for β-thal, 162 (0.39%) for Hb Bart's (γ4) hydrops fetalis, 190 (0.46%) for deletional Hb H (β4) disease and 25 (0.06%) for nondeletional Hb H disease. Of the 455 at-risk couples, 90 were already pregnant and 66 underwent PND at 10-13 weeks' gestation, resulting in 15 affected fetuses. The remaining 355 at-risk couples were still preparing for pregnancy, and they were on the list for follow-up. There is considerable scope for facilitating timely PND through improved organization and screening strategy. The pre pregnancy screening is a feasible and effective approach to thalassemia prevention.

Identification of the β thalassemia allele β–50 and analysis of the hematology data of carriers in a southern Chinese population

“…To strengthen the prevention and control of thalassemia, China established a three-level thalassemia prevention and control system (Cai et al, 2018). The process involves performing genetic diagnosis for individuals with positive hematology screening and prenatal diagnosis for individuals with positive genetic diagnosis during pregnancy (Jiang et al, 2017). Before pregnancy, the couples provide blood samples for hematology analysis.…”

Systematic review of outcomes in studies of reproductive genetic carrier screening: Towards development of a core outcome set

“…[53][54][55][56]80,89 Time points of measurement were also variable. A single time point was assessed by most studies (n = 41, 85%) and included audit data from databases between 1-30 years since screening (n = 34, 83%), 29,30,[32][33][34][35][36]38,40,42,[47][48][49]52,57,60,61,[63][64][65][67][68][69]73,74,78,81,[83][84][85][86][87][88]90,91,93 patient-reported outcomes at pre-test counselling after the decision to accept or decline was made (n = 3, 7%), 75,76,82 after maternal results but before partner results (n = 1, 2%), 39 and after results between 1-2 years since screening (n = 3, 7%). 46,51,…”

“…Intended or actual uptake was reported in 71% (n = 34) of studies. 30,[32][33][34][35][36][37][38][40][41][42]44,[48][49][50][51][52][53][55][56][57]60,61,63,65,[69][70][71][72]74,75,[77][78][79][80][84][85][86][87]89,93 The outcome domain of 'attitudes and perceptions', which includes outcomes that assess how attitudes or perceptions influence test uptake, was reported in 23% (n = 11) of studies. 37,44,54,55,62,71,72,76,80,…”

High accuracy of single‐molecule real‐time sequencing in detecting a rare α‐globin fusion gene in carrier screening population

“…The common widely used diagnostic methods for α‐thalassemia in China, such as gap‐polymerase chain reaction (Gap‐PCR) and MLPA (multiplex ligation‐dependent probe amplification), cannot identify this α fusion gene, because no deletions or duplications of this fusion gene are presented in carriers (Jiang et al., 2017). It can be identified by Sanger sequencing using special primers, but this method was not applicable to population screening in clinical practice.…”