In recent years, several rational designed therapies have been developed for treatment of mucopolysaccharidoses (MPS), a group of inherited metabolic disorders in which glycosaminoglycans (GAGs) are accumulated in various tissues and organs. Thus, improved disease-specific biomarkers for diagnosis and monitoring treatment efficacy are of paramount importance. Specific non-reducing end GAG structures (GAG-NREs) have become promising biomarkers for MPS, as the compositions of the GAG-NREs depend on the nature of the lysosomal enzyme deficiency, thereby creating a specific pattern for each subgroup. However, there is yet no straightforward clinical laboratory platform which can assay all MPS-related GAG-NREs in one single analysis. Here, we developed and applied a GAG domain mapping approach for analyses of urine samples of ten MPS patients with various MPS diagnoses and corresponding aged-matched controls. We describe a nano-LC–MS/MS method of GAG-NRE profiling, utilizing 2-aminobenzamide reductive amination labeling to improve the sensitivity and the chromatographic resolution. Diagnostic urinary GAG-NREs were identified for MPS types IH/IS, II, IIIc, IVa and VI, corroborating GAG-NRE as biomarkers for these known enzyme deficiencies. Furthermore, a significant reduction of diagnostic urinary GAG-NREs in MPS IH (n = 2) and MPS VI (n = 1) patients under treatment was demonstrated. We argue that this straightforward glycomic workflow, designed for the clinical analysis of MPS-related GAG-NREs in one single analysis, will be of value for expanding the use of GAG-NREs as biomarkers for MPS diagnosis and treatment monitoring.

近年来，已经开发出几种合理设计的疗法来治疗粘多糖贮积症（MPS），这是一组遗传性代谢性疾病，其中糖胺聚糖（GAG）在各种组织和器官中积累。因此，改进用于诊断和监测治疗效果的疾病特异性生物标志物至关重要。特定的非还原端 GAG 结构 (GAG-NRE) 已成为 MPS 有前途的生物标志物，因为 GAG-NRE 的组成取决于溶酶体酶缺陷的性质，从而为每个亚组创建特定的模式。然而，目前还没有一个简单的临床实验室平台可以在一次分析中检测所有 MPS 相关的 GAG-NRE。在这里，我们开发并应用了 GAG 域映射方法，用于分析 10 名具有各种 MPS 诊断的 MPS 患者和相应的年龄匹配对照的尿液样本。我们描述了 GAG-NRE 分析的纳米 LC-MS/MS 方法，利用 2-氨基苯甲酰胺还原胺化标记来提高灵敏度和色谱分辨率。诊断性尿 GAG-NRE 被鉴定为 MPS 类型 IH/IS、II、IIIc、IVa 和 VI，证实了 GAG-NRE 作为这些已知酶缺陷的生物标志物。此外，在接受治疗的 MPS IH (n = 2) 和 MPS VI (n = 1) 患者中，诊断性尿液 GAG-NRE 显着减少。我们认为，这种简单的糖组学工作流程专为在一次分析中对 MPS 相关的 GAG-NRE 进行临床分析而设计，对于扩大 GAG-NRE 作为 MPS 诊断和治疗监测生物标志物的使用具有重要价值。