]> 2026-07-31T12:14:43+00:00 WBR0908 0 en Absence of ¹⁴C UDP-galactose after the addition of ¹⁴C galactose-1-phosphate Classic galactosemia is characterized by the absence of galactose-1-phosphate uridyltransferase (GALT) resulting in the absence of detectable UDP ¹⁴C galactose after the addition of ¹⁴C galactose-1-phosphate as a substrate. Absence of ¹⁴C galactose-1-phosphate after the addition of ¹⁴C galactose Absence of ¹⁴C galactose-1-phosphate after the addition of ¹⁴ C galactose is observed in galactokinase deficiency. Galactokinase deficiency is a relatively mild disorder associated with early-onset cataracts with no effect on early development. Accumulation of ¹⁴C UDP-galactose after the addition of ¹⁴C galactose-1-phosphate Classic galactosemia characterized by the absence of galactose-1-phosphate uridyltransferase (GALT). The enzyme assay would reveal an absence , not accumulation, of ¹⁴C UDP-galactose after the addition of ¹⁴C galactose-1-phosphate. Accumulation of ¹⁴C UDP-galactose after the addition of ¹⁴C galactose Accumulation of ¹⁴C UDP-galactose after the addition of ¹⁴C galactose occurs in the absence of the UDP-glucose 4-epimerase (GALE) enzyme. Absence of ¹⁴C glucose-1-phosphate or ¹⁴C galactose-1-phosphate after the addition of ¹⁴C lactose. This enzyme assay finding is observed in patients with lactase deficiency, i.e. lactose intolerance. Biochemistry Elevated levels of galactose are detected in a newborn screening test and prompt further investigation for a galactose metabolism disorder. An erythrocyte enzyme assay that monitors the accumulation of products of the galactose metabolic pathway following the addition of a radiolabeled substrate is carried out. The enzyme assay confirms the diagnosis of a galactose metabolism disorder that leads to mental retardation, failure to thrive, and jaundice if galactose is not eliminated from the diet. Which of the following is most likely the result of the enzyme assay in this patient? A General Principles 2020-10-28T02:02:52Z 2459150.5853241 WBR0908