Galactose-1-phosphate uridylyltransferase (or GALT, G1PUT) is an enzyme responsible for converting ingested galactose to glucose. Deficiency of GALT causes classic galactosemia. Galactosemia is an autosomal recessive inherited disorder detectable in newborns and childhood. Classical galactosemia (G/G) is caused by a deficiency in GALT activity, whereas the more common clinical manifestations, Duarte (D/D) and the Duarte/Classical variant (D/G) are caused by the attenuation of GALT activity. Symptoms include ovarian failure, developmental coordination disorder (difficulty speaking correctly and consistently), and neurologic deficits. A single mutation in any of several base pairs can lead to deficiency in GALT activity. Screening has mostly eliminated neonatal death by G/G galactosemia, but the disease, due to GALT’s role in the biochemical metabolism of ingested galactose (which is toxic when accumulated) to the energetically useful glucose, can certainly be fatal. However, those afflicted with galactosemia can live relatively normal lives by avoiding milk products and anything else containing galactose (because it cannot be metabolized), but there is still the potential for problems in neurological development or other complications, even in those who avoid galactose.