Table 1

Diagnostic biochemical investigations

Value Reference range
Hyperprolinaemia type II
Plasma (μmol/l) (n = 5)
 Hydroxyproline6–90< 10
Urine (μmol/mmol creatinine) (n = 5)
 Proline3700–47500< 13
 Hydroxyproline85–420< 13
 Glycine1432–4055< 356
 Ornithine18–33< 8
 N-(pyrrole-2-carboxyl)-glycinePresentNot detected
Vitamin B6deficiency
Plasma (nmol/l) (n = 2)
 Pyridoxal phosphate23.5; 22.724.3–81.0
 Pyridoxic acid1.0; 2.710.9–27.3
Urine (μmol/mmol creatinine) (n = 1)
 Pyridoxic acid0.40.5–2.3
Urine (μmol/mmol creatinine)
Basal (reference) Peak
Tryptophan load test
Xanthurenic acid12.4 (0.3–1.5)3165.91-150
Kynurenic acid2.5 (0.8–3.0)524.91-150
Kynurenine3.1 (1.1–3.7)545.51-150
2-AminoacetophenoneNot detectedPresent1-151
  • Plasma vitamin B6 was measured by high performance liquid chromatography (Dunn Nutrition Centre, Cambridge; department of clinical biochemistry, Glasgow Royal Infirmary). Tryptophan metabolites and pyridoxic acid were measured in urease treated extracted urine by gas chromatography mass spectrometry with single ion monitoring. Basal values are compared with in house paediatric reference ranges.

  • 1-150 Reference is less than 10-fold increase above basal;

  • 1-151 Not reported