Background Sphingolipids play a crucial role in cellular functions and are essential components of cell membranes, signaling molecules, and lipid metabolism. In particular, ceramide is a key intermediate in sphingolipid metabolism and defects in ceramide metabolism can lead to various inborn errors of metabolism, making ceramides important targets for clinical screening and diagnosis. Detecting altered concentration patterns of sphingolipids is desirable for distinguishing related inborn errors of metabolism for diagnosis and treatment monitoring. Methods We developed a liquid chromatography-tandem mass spectrometry method with a pathway-oriented approach to focus on sphingolipids involved in ceramide metabolism. A total of 47 sphingolipids bearing different head groups and side chains were targeted. Precision/reproducibility, linearity, and spike recovery extraction efficiency tests were performed on plasma and serum samples from confirmed cases of sphingolipidosis. Results Linearity of the method showed the coefficient of determination (r2) for all standards to be >0.99 with a slope of 1.00 ± 0.01. Intra- and interday reproducibility of standards spiked into plasma and serum revealed a coefficient of variation <20%. Spike and recovery assessment showed recovery values of 80%–120% for all standards. Altered levels of sphingolipids from patients with hereditary sensory and autonomic neuropathy caused by pathogenic variants in SPTLC2 and hypomyelinating leukodystrophy related to variants in DEGS1 were detected, in agreement with trends reported in earlier studies confirming the utility of this pathway-centric method. Conclusions This method can serve as a useful tool to simultaneously monitor sphingolipids, enabling screening and diagnosis of inborn errors of ceramide metabolism.

中文翻译：

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开发用于诊断先天性神经酰胺代谢缺陷的多重鞘脂方法


背景 鞘脂在细胞功能中发挥着至关重要的作用，是细胞膜、信号分子和脂质代谢的重要组成部分。尤其是神经酰胺是鞘脂代谢的关键中间体，神经酰胺代谢缺陷可导致各种先天性代谢缺陷，使神经酰胺成为临床筛查和诊断的重要靶点。检测鞘脂浓度模式的改变对于区分相关的先天性代谢错误以进行诊断和治疗监测是可取的。方法我们开发了一种液相色谱-串联质谱法，采用以通路为导向的方法，重点关注参与神经酰胺代谢的鞘脂。总共 47 种带有不同头基和侧链的鞘脂被作为目标。对鞘脂沉积症确诊病例的血浆和血清样本进行了精密度/再现性、线性和加标回收率提取效率测试。结果 该方法的线性显示所有标准品的测定系数 (r2) 均为 >0.99，斜率为 1.00 ± 0.01。添加到血浆和血清中的标准品的日内和日间重现性显示变异系数为<20%。加标和回收率评估显示所有标准品的回收率为 80%–120%。检测到由 SPTLC2 致病性变异引起的遗传性感觉和自主神经病患者以及与 DEGS1 变异相关的低髓鞘性脑白质营养不良患者的鞘脂水平发生改变，这与早期研究报告的趋势一致，证实了这种以通路为中心的方法的效用。 结论该方法可以作为同时监测鞘脂的有用工具，从而能够筛查和诊断先天性神经酰胺代谢缺陷。