Analysis of Creatine Metabolites Using Gas Chromatography - Mass Spectrometry

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Laboratorinė medicina. 2011,
t. 13,
Nr. 3,
p. 115 -
123

Analysis of Creatine Metabolites Using Gas Chromatography - Mass Spectrometry

Milda Banytė, Jurgita Songailienė, Vaidutis Kučinskas

 

The aim. To determine the cause of in­tellectual disability by quantitative creatine metabolites (creatine and guanidinoacetato) analysis by gas chro­matography - mass spectrometry.

Materials and methods. Urine samples of 30 patients, who do not have metabolic disorders, according to organic acids, aminoacids and glicosamine glycans analysis, were selected and ana­lysed. Ages of selected patients range from 1 to 15 years. The families that were consulted in Vilnius University Hospital “Santariškių Clinics” Centre for Medical Genetics in the Genetic counseling sec­tion since 2008-2010 and genetic testing of these families has not revealed the cause of intellectual disability were cho­sen. Creatine and guanidinoacetate con­centrations in urine samples were mea­sured by gas chromatography - masss spectrometry using SIM method.

Results. Guanidinoacetate concen­trations in collected urine samples ranged from 4.93 to 109.1 mmol/mol creatinine and values were normal ac­cording to those in the publications (4-220). Creatine concentrations in col - lected urine samples in the first age group (up to 4 years) showed that creatinine level in one patient exceeded the maximum concentration. Guanidino- acetate levels of this patient were within the normal range, so the patient is sus­pected of creatine transporter deficiency. Creatine con cen trations in col lected urine samples in the second age group (from 4 to 12 years) ranged from 21.42 to 474.3 mmol/mol creatinine, values fit well with the normal range indicated in literature (17-720). Creatine concentra­tions in collected urine samples in the third age group (> 12 years) varied from 9.53 to 366 mmol/mol creatinine, values correspond well to the data in the publi­cations.

Conclusions. Gas chromatography - mass spectrometry SIM method was used to examine 30 patients with intellectual disability urine samples, quantitative analysis of creatine and guanidino- acetate was performed. Two patients were suspected of creatine metabolism disorders: creatine transporter deficiency and AGAT deficiency.

Keywords: SIM method, creatine, guanidinoacetate, creatine transporter deficiency, AGAT deficiency.

 

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