Brief Answer:
Galactosemia

Detailed Answer:
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Let me try to address the issues:
1. XXXXXXX is possibly suffering from Galactosemia. It is due deficiency of the enzymes needed to break down galactose of milk. Three possible enzymes involved in the metabolism of galactose: galactokinase, transferase or epimerase.
2. Any single deficient enzyme can result in cataract through the accumulation of galactitol in the lens.
3. An elevated blood galactose concentration as the result of altered metabolism of galactose due to a genetic deficiency in enzyme activity or secondary hypergalactosemia due to liver disease like congenital hepatitis is the cause of the jaundice.
4. Galactose is a reducing sugar but not same as glucose. Galactosuria or galactose in urine is detected by the dipstick test.
5. It is genetic. Mutations in the GALT, GALK1, and XXXXXXX genes cause galactosemia.
6. Lactose and galactose need to be taken out of his diet. Instead, he is to be given soy-based formula. Untreated galactosemia can cause rapid, unexpected death due to an infection that invades the blood. Untreated galactosemia may also develop brain damage, liver disease alongside cataracts.

Regards

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Brief Answer:
Explanation provided

Detailed Answer:
1. Lactose of milk breaks into glucose and galactose. Due to problems of metabolism glucose cannot enter ETC. Galactose gets reduced to galactitol and cannot enter the electron transport chain.
2.Thus ATP production suffers.

Regards

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