The enzyme deficient in Galactosemia is:

Ref. Textbook of Biochemistry for Medical Students. Page. 183 Galactosemia is an autosomal recessive trait that results from a defective gene encoding either galactokinase or galactose 1-P uridyltransferase. There are
over 100 heritable mutations that can cause galactosemia, and the incidence is approximately 1 in 60,000 births. Galactose will be present in elevated amounts in the blood and urine and can result in decreased glucose synthesis and hypoglycemia. Galactosemia symptoms often begin around day 3 in a newborn and include the hallmark cataracts. Jaundice and hyperbilirubinemia do not resolve if the infant is treated with phototherapy Severe bacterial infections ( E.coli sepsis) are common
in untreated galactosemic infants. Failure to thrive, lethargy, hypotonia, and mental retardation are other common and apparent features