Urinary homogentisic acid in alkaptonuric and healthy children.
To detect and follow-up the metabolic status of patients with alkaptonuria (AKU), urinary homogentisic acid (HGA) was measured by gas chromatography. These results were close to values we obtained by colorimetric method (linearity: upto 700 mg/l, detection limit: 1 mg/l, within-run imprecision (CV): 1.2% at 100 mg/l HGA, 4.9% at 10 mg/l, between-run CV: 6.8% at 100 mg/l). To determine urinary reference ranges of HGA, 84 healthy children (age: 2 months-18 years) were divided into five age groups. HGA and creatinine were measured in their morning urine. Statistical analysis proved that urinary HGA/creatinine ratio is age-dependent. The ratio is relatively high between 1 and 6 years of age, with large scatter (upper limit of reference ranges given as mean + 2 SD: 5.5-7.2 mg/mmol = 0.03-0.04 mmol/mmol creatinine), and it decreases with age. Approximately at the age of 7 years, HGA/creatinine ratio becomes constant, and later it is similar to the adult value (upper limit: 2.8 mg/ mmol = 0.017 mmol/mmol creatinine). We monitored a patient during her 1-5th year of life, and her urinary HGA was 80-200 times higher than the upper limit of the age-matched reference ranges. The measurement of HGA supports the decision for starting restricted protein diet and is useful for the evaluation of the effectiveness of therapy.
Oláh
Anna V
AV
Department of Clinical Biochemistry and Molecular Pathology, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary. olaha@jaguar.dote.hu
Llyés
István
I
Szoke
Attila
A
Csízy
István
I
Tóth
Judit
J
Varga
József
J
D000293:Adolescent; D017677:Age Distribution; D000474:Alkaptonuria / Q000188:drug therapy / Q000652:urine*; D000975:Antioxidants / Q000627:therapeutic use; D001205:Ascorbic Acid / Q000627:therapeutic use; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002849:Chromatography, Gas; D003124:Colorimetry; D003404:Creatinine / Q000652:urine; D006713:Homogentisic Acid / Q000652:urine*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn
D000975:Antioxidants; D003404:Creatinine; D006713:Homogentisic Acid; D001205:Ascorbic Acid