Galactose-1-phosphate uridyl transferase deficiency due to Duarte/galactosemia combined variation: clinical and biochemical studies.

The most common abnormality detected by the screening of newborn infants for galactosemia is a deficiency of galactose-1-phosphate uridyl transferase due to the presence in one individual of allelic genes for the Duarte variant and for galactosemia. Clinical studies of ten untreated individuals with this genetic compound, including three adults, failed to reveal evidence of cataracts, liver disease, or mental subnormality, the major clinical complications associated with galactosemia. Galactose-1-phosphate was not detectable in umbilical cord blood from one infant. Galactose was not detectable in random blood specimens from any of the individuals and was present in only small amounts following ingestion of milk in one infant and a child. It would appear that this common gentic variation is usually, if not always, benign.