Newborn Screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Florence, Italy.
Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Neuroscience Department, Meyer Children's Hospital, Florence, Italy.
Clin Chem Lab Med. 2021 Apr 30;59(9):1516-1526. doi: 10.1515/cclm-2021-0316. Print 2021 Aug 26.
Fabry disease (FD) is an X-linked lysosomal storage disorder, resulting from a deficiency of the enzyme α-galactosidase A, responsible for breaking down glycolipids such as globotriaosylceramide and its deacylated derivative, globotriaosylsphingosine (LysoGb3). Here, we compare the levels of LysoGb3 in dried blood spots (DBS) and plasma in patients with classic and late-onset phenotypes.
LysoGb3 measurements were performed in 104 FD patients, 39 males and 65 females. Venous blood was collected. A portion was spotted onto filter paper and another portion separated to obtain plasma. The LysoGb3 concentrations in DBS and plasma were determined by highly sensitive electrospray ionization liquid chromatography tandem mass spectrometry. Agreement between different matrices was assessed using linear regression and Bland Altman analysis.
The method on DBS was validated by evaluating its precision, accuracy, matrix effect, recovery, and stability. The analytical performances were verified by comparison of a total of 104 paired DBS and plasma samples from as many FD patients (representing 46 variants). There was a strong correlation between plasma and the corresponding DBS LysoGb3 concentrations, with few exceptions. Discrepancies were observed in anemic patients with typically low hematocrit levels compared to the normal range.
The method proved to be efficient for the rapid analysis of LysoGb3. DBS provides a convenient, sensitive, and reproducible method for measuring LysoGb3 levels for diagnosis, initial phenotypic assignment, and therapeutic monitoring in patients with FD.
法布里病（FD）是一种 X 连锁溶酶体贮积症，由α-半乳糖苷酶 A 缺乏引起，该酶负责分解糖脂，如神经节苷脂和其去酰基衍生物神经节苷脂鞘氨醇（LysoGb3）。在这里，我们比较了经典和迟发型表型患者的干血斑（DBS）和血浆中 LysoGb3 的水平。
对 104 例 FD 患者（39 名男性和 65 名女性）进行 LysoGb3 测量。采集静脉血。一部分点在滤纸上，另一部分分离以获得血浆。DBS 和血浆中的 LysoGb3 浓度通过高灵敏度电喷雾电离液相色谱串联质谱法测定。使用线性回归和 Bland Altman 分析评估不同基质之间的一致性。
通过评估 DBS 的精密度、准确度、基质效应、回收率和稳定性对其进行了验证。通过比较总共 104 对来自 104 例 FD 患者（代表 46 种变异）的 DBS 和血浆样本，验证了分析性能。除少数例外外，血浆和相应 DBS LysoGb3 浓度之间存在很强的相关性。与正常范围相比，贫血患者的血细胞比容水平通常较低，存在差异。
该方法被证明对 LysoGb3 的快速分析非常有效。DBS 为 FD 患者的诊断、初始表型分配和治疗监测提供了一种方便、灵敏和可重复的 LysoGb3 水平测量方法。
