Galactitol in galactosemia

Abstract

Urinary galactose and galactitol excretion in controls is age-dependent with the highest concentrations at a younger age. Untreated patients with classical galactosemia excreted highly elevated amounts of galactitol (8000–69 000 mmol/mol creatinine; controls 3–81) which did not correlate with galactose excretion. After treatment, galactose excretion returned to normal in all patients whereas galactitol excretion (45–900 mmol/mol creatinine) remained above the age-matched control range. The excretion of galactitol (96–170 mmol/mol creatinine) in untreated compound heterozygotes was much lower although still above the age-matched control levels, and it returned to normal after treatment. In untreated classical galactosemia patients the galactitol in plasma (120–500 μmol/l) was markedly elevated (controls 0.08–0.86 μmol/l); under treatment, the galactitol concentrations (4.7–20 μmol/l) remained above the control range in all. There was no correlation with age nor with galactose-1-phosphate and UDP-galactose levels. Two untreated compound heterozygotes had elevated plasma galactitol (6.0 and 63 μmol/l) which, when treated, returned to normal.