Congenital disorders of glycosylation (CDG) are caused by defects in various genes governing glycoconjugate biosynthesis. Several responsible genes have been identified in the protein N‐glycosylation process. Analyses of mucin‐type core‐1 O‐glycoform of apolipoprotein C‐III (apoCIII) have recently revealed combined N‐ and O‐glycosylation defects. We applied matrix‐assisted laser desorption/ionization mass spectrometry profiling of apoCIII glycoforms to 500 serum samples for CDG screening, and reference values were determined. The content of unglycosylated apoCIII was low in early infancy, indicating that the O‐glycan occupancy should be assessed based on age‐matched reference values. The samples from patients with mutations in the ALG1, ATP6V0A2, B4GALT1, COG2, GCS1, PGM1, SLC35A2, and TRAPPC11 genes were analyzed. B4GALT1‐ and TRAPPC11‐CDG were accompanied by under‐sialylation of O‐glycans and are now recognized as combined N‐ and O‐glycosylation disorders.

中文翻译：

---

通过基质辅助激光解吸/电离质谱法对 500 份血清样本进行载脂蛋白 C-III O-糖型分析，用于诊断先天性糖基化疾病

先天性糖基化障碍 (CDG) 是由控制糖缀合物生物合成的各种基因缺陷引起的。已经在蛋白质N-糖基化过程中鉴定了几个相关基因。最近对载脂蛋白 C-III (apoCIII)的粘蛋白型 core-1 O-糖型的分析揭示了N-和O-糖基化的组合缺陷。我们将 apoCIII 糖型的基质辅助激光解吸/电离质谱分析应用于 500 份血清样本以进行 CDG 筛选，并确定参考值。婴儿早期未糖基化的 apoCIII 含量较低，表明O应根据年龄匹配的参考值评估-聚糖占有率。分析了来自具有ALG1、ATP6V0A2、B4GALT1、COG2、GCS1、PGM1、SLC35A2和TRAPPC11基因突变的患者的样本。B4GALT1- 和 TRAPPC11-CDG 伴随着O-聚糖的唾液酸化不足，现在被认为是N-和O-糖基化联合疾病。