Galactose and galactitol in the urine of children with compound heterozygosity for Duarte variant and classical galactosemia (GtD/gt) after an oral galactose load.

An oral dose of galactose, 1 g/kg of body weight, was administered to 24 children with the Duarte variant/classical galactosemia genetic compound (GtD/gt) and to 16 controls ranging in age from 0.3 to 10.7 years. Urine was then collected for 3h. Excreted amounts of galactose and galactitol increased with age in all subjects, but were consistently greater in the compound heterozygotes. If related to urinary creatinine, galactosuria and galactitoluria were no longer age-dependent, although as compared with the controls, urinary galactose was about three times and urine galactitol twice as high in the patients (p less than 0.01 for both). We found a statistically significant correlation between urinary galactitol and galactose in these patients. Moreover, urinary galactitol and galactose each correlated positively with the area under the plasma galactose curve, as well as with the peak value for plasma galactose after galactose ingestion.