Small Group 1 - Problem 2 Flashcards
A male and female sibling were described as having neonatal jaundice, poor muscle tone, enlarged liver and cataracts. The estimated I.Q. in the young children was low (50-60). These children also exhibited delayed speech and poor coordination. Subsequently a newborn sibling was identified as having the same genetic defect. This child was immediately placed on a lactose-free diet. These children have a deficiency in galactose 1-phosphate uridyl transferase.
What are the two enzyme defects that cause galactosemia?
Galactokinase or galactose 1-phosphate uridyl transferase.
Which form of galactosemia is more common and more severe?
Galactose 1-phosphate uridyl transferase deficiency
What symptoms are detected when galactose 1-phosphate uridyl transferase is absent?
An accumulation of galactose 1P in all tissues, blood, and increased formation of galactitol via aldose reductase
What happens as a result of galactose 1-phosphate accumulation in tissues?
Malfunction of the GI tract, liver, kidney, brain, and ultimately death if left untreated.
What do the high levels of galactose in blood result in?
A spillover of galactose into the urine
What happens as a result of increased formation of galactitol
Cataracts: galactitol depletes the lens of NADPH.
Explain why the youngest sibling was placed on a lactose free diet.
Lactose is the major source of galactose in the diet. It is a disaccharide of glucose and galactose. The youngest sibling was placed on this diet to prevent the potential damage caused by the enzyme deficiency.
What are the symptoms associated with galactokinase deficiency
Galactose in the blood and urine; cataracts
What are the symptoms associated with uridyl transferase deficiency?
More common and severe galactose in the blood and urine; cataracts; dysfunction of liver, kidney, spleen, intestine, and brain death
