Abstract

Hemoglobin Constant Spring (Hb CS) and Hb Pakse' (PS) are the common non-deletional α⁺-thalassemia found in Thailand. These two variants can cause severe thalassemia syndromes, especially in fetus and neonate. Molecular diagnosis is the only confirmatory method because Hb CS and Hb PS are usually missed by routine screening and Hb analysis. Therefore, we aimed to develop rapid direct PCR for the diagnosis of Hb CS and PS genes. Multiplex direct PCR assays for identifying the Hb CS and PS genes in whole blood (WB) and amniotic fluid (AF) specimens were developed. The assays were firstly validated on 290 unrelated whole blood specimens. Hb CS and PS carriers were identified in 67 (23.1%) and 6 (2.1%) cases, respectively. A 100% concordant result as compared to routine PCR assay was observed. The direct PCR assays have been applied successfully for prenatal diagnosis in two families. The result showed that the fetuses were affected by homozygous Hb CS and compound heterozygous Hb CS/Hb PS. Accurate prenatal diagnosis of these families was observed using the newly developed assays. These assays should be applicable in routine thalassemia diagnostics as well as in the large-scale screening of Hb CS and PS in the region.

摘要

血红蛋白恒定弹簧 (Hb CS) 和 Hb Pakse' (PS) 是常见的非缺失 α ⁺-在泰国发现的地中海贫血。这两种变体可导致严重的地中海贫血综合征，尤其是在胎儿和新生儿中。分子诊断是唯一的确认方法，因为常规筛查和 Hb 分析通常会遗漏 Hb CS 和 Hb PS。因此，我们旨在开发用于诊断 Hb CS 和 PS 基因的快速直接 PCR。开发了用于鉴定全血 (WB) 和羊水 (AF) 标本中 Hb CS 和 PS 基因的多重直接 PCR 测定。该测定首先在 290 个不相关的全血样本上进行了验证。分别在 67 例（23.1%）和 6 例（2.1%）病例中发现了 Hb CS 和 PS 携带者。与常规 PCR 测定相比，观察到 100% 一致的结果。直接 PCR 检测已成功应用于两个家庭的产前诊断。结果表明，胎儿受到纯合Hb CS和复合杂合Hb CS/Hb PS的影响。使用新开发的检测方法观察到这些家庭的准确产前诊断。这些检测应适用于常规地中海贫血诊断以及该地区 Hb CS 和 PS 的大规模筛查。