Question

Galactosemia is a disease caused by a genetic defect that affects an individual's ability to correctly metabolize galactose for use in the glycolytic pathway, but has no effect on metabolism of starch and glycogen, or on glycolysis. Galactosemia results in high galactose levels in the blood and accumulation of galactose-1-phosphate in the tissues.

e) Propose possible candidates for the defective enzyme that causes galactosemia.

Answer 1

Enzyme GALT is responsible for galactosemia. Galactosemia is a defect in the metabolism of galactose. The main enzyme which is non-functional or missing in galactosemia is Galt or galactose 1 phosphate uridyltransferases . Galactose is a monosaccharide mostly present in breast milk, cow's milk and other dairy products. Galactose is a sugar , product of lactose. The enzyme GALT is present in liver and help in galactose break down. When galactose cannot converted to glucose or any of the by product like galactose 1 phosphate , it start accumulating in the tissues and affect other part of the body .

Galactosemia is a Autosomal recessive disease . Mutation in GALE, GAK1 and GALT gene can cause galactosemia.

GALT enzyme that is galactose 1phosphate uridyltransferases is only involved in galactose metabolism so the other carbohydrates like starch , glycogen and glucose can metabolise normally in galactosemia.