The TREC/KREC Assay for the Diagnosis and Monitoring of Patients with DiGeorge Syndrome

DiGeorge syndrome (DGS) presents with a wide spectrum of thymic pathologies. Nationwide neonatal screening programs of lymphocyte production using T-cell recombination excision circles (TREC) have repeatedly identified patients with DGS. We tested what proportion of DGS patients could be identified at birth by combined TREC and kappa-deleting element recombination circle (KREC) screening. Furthermore, we followed TREC/KREC levels in peripheral blood (PB) to monitor postnatal changes in lymphocyte production.MethodsTREC/KREC copies were assessed by quantitative PCR (qPCR) and were related to the albumin control gene in dry blood spots (DBSs) from control (n = 56), severe immunodeficiency syndrome (SCID, n = 10) and DGS (n = 13) newborns. PB was evaluated in DGS children (n = 32), in diagnostic samples from SCID babies (n = 5) and in 91 controls.ResultsAll but one DGS patient had TREC levels in the normal range at birth, albeit quantitative TREC values were significantly lower in the DGS cohort. One patient had slightly reduced KREC at birth. Postnatal DGS samples revealed reduced TREC numbers in 5 of 32 (16%) patients, whereas KREC copy numbers were similar to controls. Both TREC and KREC levels showed a more pronounced decrease with age in DGS patients than in controls (pConclusionsThe combined TREC/KREC approach with correction via control gene identified 1 of 13 (8%) of DiGeorge syndrome patients at birth in our cohort. The majority of patients had TREC/KREC levels in the normal range.迪乔治综合征（DiGeorge syndrome, DGS）可表现出广泛的胸腺病理谱。采用T细胞重组切除环（T-cell recombination excision circles, TREC）检测淋巴细胞生成的全国新生儿筛查项目，已多次检出迪乔治综合征患者。本研究旨在探究联合T细胞重组切除环与κ删除元件重组环（kappa-deleting element recombination circle, KREC）筛查，可在新生儿期检出多少比例的迪乔治综合征患者。此外，我们还对受试者外周血（peripheral blood, PB）中的TREC/KREC水平进行追踪，以监测淋巴细胞生成的产后变化。 方法 本研究通过实时定量聚合酶链反应（quantitative PCR, qPCR）对TREC/KREC拷贝数进行检测，并以白蛋白对照基因作为内参，分析对照组（n=56）、重症联合免疫缺陷综合征（severe immunodeficiency syndrome, SCID, n=10）及迪乔治综合征（n=13）新生儿的干血斑（dry blood spots, DBSs）样本。同时对32名迪乔治综合征患儿、5名重症联合免疫缺陷综合征患儿的诊断样本及91名对照个体的外周血样本进行检测。 结果 除1名迪乔治综合征患者外，其余所有患者出生时的TREC水平均处于正常范围，但迪乔治综合征队列的定量TREC值显著低于对照组。有1名患者出生时的KREC水平轻度降低。产后迪乔治综合征患者样本显示，32名患者中有5名（16%）的TREC数量降低，而KREC拷贝数与对照组无显著差异。迪乔治综合征患者的TREC与KREC水平随年龄增长的下降幅度均显著大于对照组（原文此处P值未完整标注）。 结论 通过对照基因校正的联合TREC/KREC筛查方案，在本队列中仅可在新生儿期检出13名迪乔治综合征患者中的1名（占比8%）。大部分患者的TREC/KREC水平处于正常范围。