Akademik Veri Yönetim Sistemi
SSIEM Annual Symposium, Freiburg, Almanya, 30 Ağustos - 02 Eylül 2022, cilt.45, sa.1418955, ss.687
Background: Creatine metabolism disorders (GAMT deficiency, AGAT deficiency, and transport defects) are an important group among inherited metabolic diseases that cause neurological defects. Early diagnosis is important for the effectiveness of treatment and the prevention of permanent neurologic sequelae. Simultaneous measurements of guanidinoacetate (GA), creatine(C), and creatinine in plasma and urine are used in the diagnosis of creatine metabolism disorders.Case Study / Methods: GA and C levels in plasma and urine samples were measured by LC-MS/MS method by forming butanolHCl derivative. ERNDIM external quality control materials and in-house prepared control samples were used in analytical performance studies. EDTA plasma and spot urine samples were used for analyses. Results: While the within-run reproducibility CV values were between 2.9-9.9% for GA and 5.5-10.7% for creatine, inter-run reproducibility CV values were 3.3-8.6% for GA and 4.9-7.9% for C. Bias values were found as (-13.8)-(12.4) % for GA and(-20.3)-(13.8) for C. In the reference interval verification study, the GA and C values of 140 patients without creatine defect were within the specified reference range, while the values of the cases previously diagnosed with GAMT and creatine transport defect were found to be compatible with their diseases and the literature. Conclusion / Discussion: Measurement of plasma and urine GA, C and creatinine levels together are used in the diagnosis of creatine metabolism disorders. Early diagnosis of creatine metabolism disorders is important for the prevention of permanent neurological damage. More patients' access to these tests will increase diagnostic efficiency. In this study, it was seen that the measurement of creatine metabolites by LC-MS/MS is fast, and acceptable in terms of repeatability and bias, and its analytical performance is sufficient for screening and diagnosis of creatine metabolism disorders. Keywords: Creatine metabolism disorders, guanidinoacetate, creatine, GAMT deficiency, AGAT deficiency