Step 1: Enzyme's Metabolic Function.
Galactose-1-phosphate uridyltransferase is essential for the Leloir pathway, converting galactose to glucose-1-phosphate for energy. A deficiency leads to toxic accumulation of galactose-1-phosphate, particularly in the liver, kidney, and brain.
Step 2: Understanding Galactosaemia.
Galactosaemia is a rare, autosomal recessive metabolic disorder. Affected newborns may exhibit vomiting, diarrhea, poor growth, enlarged liver, jaundice, and cataracts due to galactose buildup. Untreated, it can cause intellectual disability, liver cirrhosis, and death. Dietary restriction of galactose and lactose is the sole treatment.
Step 3: Eliminating Alternative Conditions.
- (B) Haemochromatosis: Characterized by excessive iron absorption, unrelated to galactose metabolism.
- (C) Wilson's Disease: A disorder of copper metabolism, not linked to galactose.
- (D) Reye's Syndrome: A rare condition associated with viral infections and aspirin use, not a consequence of galactose metabolism.
Step 4: Conclusion.
Therefore, the correct diagnosis is Galactosaemia, resulting from a deficiency in galactose-1-phosphate uridyltransferase.