Quantification of glutaric and 3-hydroxyglutaric acids in urine of glutaric acidemia type I patients by HPLC with intramolecular excimer-forming fluorescence derivatization.
BACKGROUND
Glutaric aciduria type I (GA1) is an autosomal recessive disorder that usually causes neurological damage. Early diagnosis of the disease prior to the appearance of clinical symptoms can lead to better outcomes.


METHODS
We describe a simple and selective HPLC method with intramolecular excimer-forming fluorescence derivatization to diagnose GA1. Glutaric acid (GA) and 3-hydroxyglutaric acid (3HGA) in urine and an internal standard were derivatized with 1-pyrenebutyric hydrazide (PBH). The derivatives were separated on a C18 column and fluorometrically detected at 475 nm (excitation of 345 nm) with a run time of 18 min.


RESULTS
Excellent linearity over a wide range, reproducibility (coefficient of variation < or =14.5%), and sensitivity (limit of detection 0.4 micromol/l 3HGA and 0.2 micromol/l GA) were obtained. A retrospective study on previously diagnosed GA1 patients' urine from our laboratory archives between 1999 and 2004 was performed by analysts blinded to the study.


CONCLUSIONS
The method enabled us to differentiate GA1 cases (n=36) from controls (n=99), regardless of the years of urine storage. The method is valuable for both retrospective and prospective diagnoses of GA1.
Al-Dirbashi
Osama Y
OY
Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia.
Jacob
Minnie
M
Al-Amoudi
Mohammed
M
Al-Kahtani
Khalid
K
Al-Odaib
Ahmed
A
El-Badaoui
Fahad
F
Rashed
Mohamed S
MS
D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005977:Glutarates / Q000097:blood / Q000652:urine*; D006801:Humans; D008661:Metabolism, Inborn Errors / Q000652:urine*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*
C108959:3-hydroxyglutaric acid; D005977:Glutarates; C035736:glutaric acid