Galactosaemia

Question 1

What is galactosaemia?

Answer 1

Deficiency in any of the following enyzymes;
Galactokinase
Uridyl transferase
UDP-galactose epimerase

Because the conversion of galactose to galactitol is favoured

Question 2

What are the symptoms of galactosaemia?

Answer 2

Hepatomegaly and cirrhosis 
Renal failure
Vomiting 
Seizures and brain damage
Cataracts
Hypoglycaemia
Poor growth in the first few weeks of life

Question 3

How can galactosaemia result in more ROS damage?

Answer 3

The galactose in dietary milk is converted into galactitol more favourable (because there is a lack of important enzymes).
The conversion of galactose to galactitol requires NADPH (and aldose reductase enzymes). Increase activity of this enzyme consumes excess NADPH. This results in less being available for glutathione in its antioxidant work. Therefore you are compromised in your defence against ROS damage

Question 4

What are the consequences of an absence of uridyl transferase resulting in galactosaemia?

Answer 4

There is a build up of galactose 1-p which is toxic to cells (particularly in liver, kidney and brain)

The compound is a phosphate sequester and interferes with atp synthesis because it steals the phosphate needed to convert ADP to ATP

Question 5

Galactitol can also be found in the urine of someone who has galactosaemia. What is it and how is it formed?

Answer 5

Sugar alcohol

Made through the reduction of galactose by the enzyme aldose reductase

Question 6

Why might someone with galactosaemia develop jaundice?

Answer 6

Jaundice is caused by a build up of bilirubin, which is often broken down and deposed of appropriately by the liver, the liver however is unable to function properly due to the tissue damage from the galactose 1P build up