Using Liquid Chromatography-Tandem Mass Spectrometry in Detecting Plasma Lyso-GL3 Levels in Patients with Fabry Disease and the Association Analysis of Phenotype-Genotype of the Disease

Objective Using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the plasma level of Lyso-GL3 in patients with Fabry disease and to analyze the clinical application of the method.

Methods Thirty-nine patients with a genetic diagnosis of Fabry disease were included, and plasma levels of Lyso-GL3 were measured by LC-MS/MS analysis, and detailed clinical information of the patients was obtained including: α-galactosidase A activity, genetic variants, quantification of urine protein, mean arterial pressure, and estimation of glomerular filtration rate, and the differences in the levels of Lyso-GL3 in different clinical phenotypes and genotypes were statistically analyzed, as well as the association with clinical indicators.

Results Lyso-GL3 showed good linearity within 0.7856-400 ng/mL(r=0.9992).Further analysis of 39 Fabry disease patients diagnosed in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine showed a median Lyso-GL3 concentration of 23.6 ng/mL(4.3-92.9 ng/mL); Lyso-GL3 levels were significantly higher in patients with both the frameshift and the splicing mutations, as well as in patients with the nonsense mutations, than in patients with the missense mutations (median value 119.7 ng/mL vs. 11.9 ng/mL, P=0.006, and median value 97.0 ng/mL vs. 11.9 ng/mL, P=0.015, respectively). Whereas, association analysis revealed that Lyso-GL3 was not significantly associated with urinary protein, mean arterial pressure and estimated glomerular filtration rate.

Conclusions The using of LC-MS/MS to quantify plasma Lyso-GL showed significant differences in Lyso-GL3 concentrations between classical and atypical phenotypes, suggesting that plasma Lyso-GL3 may help with clinical phenotypes. However, Lyso-GL3 levels is found to be overlapped between genotypes. No significant linear correlation was found between Lyso-GL3 and renal clinical indicators, suggesting the urgent need in finding a more accurate tool to assess renal involvement and prognosis in patients with Fabry disease.