Question
Which of the following is not an inborn error of metabolism?
| A. | Thalassaemia |
| B. | Wilson’s disease |
| C. |
Phenylketonuria |
| D. |
Galactosaemia |
|
Correct Answer � A Explanation |
 |
Inborn errors of metabolism (IEMs) are genetic disorders caused by deficiencies or dysfunctions in enzymes that are involved in metabolic pathways of carbohydrates, amino acids, lipids, or metals.
These disorders are usually inherited in an autosomal recessive pattern and typically lead to accumulation of toxic metabolites or deficiency of essential compounds, often presenting in infancy or childhood.
Thalassaemia
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Thalassaemia is a genetic hemoglobinopathy, not a metabolic disorder.
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It results from mutations in globin genes (α or β chains), leading to defective hemoglobin synthesis.
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It does not involve enzyme defects or metabolic pathways.
Reason to rule out other options:
B. Wilson’s disease – Inborn error of metabolism
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Caused by a mutation in the ATP7B gene, affecting copper metabolism.
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Leads to copper accumulation in the liver, brain, cornea (Kayser-Fleischer rings).
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It is a classical IEM of metal metabolism.
C. Phenylketonuria (PKU) – Inborn error of metabolism
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Due to deficiency of the enzyme phenylalanine hydroxylase.
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Leads to accumulation of phenylalanine, causing intellectual disability if untreated.
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Managed with low-phenylalanine diet.
D. Galactosaemia – Inborn error of metabolism
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Due to deficiency of galactose-1-phosphate uridyltransferase (GALT).
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Leads to accumulation of galactose-1-phosphate, causing liver damage, cataracts, and failure to thrive.
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Requires elimination of galactose from the diet.
