Genetic and metabolic disorders: alpha-1 antitrypsin deficiency: practice question

A Pediatrics question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pediatrics · Genetic and metabolic disorders: alpha-1 antitrypsin deficiency

Sample item

A 2-month-old has prolonged cholestatic jaundice, pale stools and hepatomegaly. Sweat chloride is normal, urine reducing substances are absent, and liver biopsy shows periodic acid-Schiff positive, diastase-resistant globules in periportal hepatocytes. Which test confirms the diagnosis?

ARed cell galactose-1-phosphate uridyltransferase assayBUrine succinylacetone estimationCSerum alpha-1 antitrypsin level with Pi phenotypingDSerum ceruloplasmin with 24-hour urinary copper

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Serum alpha-1 antitrypsin level with Pi phenotyping

Alpha-1 antitrypsin deficiency (PiZZ) causes neonatal cholestasis from retained misfolded protein in hepatocytes, seen as PAS-positive, diastase-resistant globules. Confirmation is by serum level with Pi phenotype or genotype. Lung disease follows later in life.

Option by option

A. Red cell galactose-1-phosphate uridyltransferase assay
The galactose-1-phosphate uridyltransferase assay diagnoses galactosaemia, which has urine reducing substances.
B. Urine succinylacetone estimation
Urine succinylacetone is raised in hereditary tyrosinaemia type 1, which has coagulopathy and renal tubulopathy.
C. Serum alpha-1 antitrypsin level with Pi phenotyping (correct)
Correct. A low alpha-1 antitrypsin level with Pi typing confirms the diagnosis.
D. Serum ceruloplasmin with 24-hour urinary copper
Ceruloplasmin and urine copper test for Wilson disease, which does not present in early infancy.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is C, Serum alpha-1 antitrypsin level with Pi phenotyping. Alpha-1 antitrypsin deficiency (PiZZ) causes neonatal cholestasis from retained misfolded protein in hepatocytes, seen as PAS-positive, diastase-resistant globules.

Why is "Red cell galactose-1-phosphate uridyltransferase assay" not the answer?

The galactose-1-phosphate uridyltransferase assay diagnoses galactosaemia, which has urine reducing substances.

Why is "Urine succinylacetone estimation" not the answer?

Urine succinylacetone is raised in hereditary tyrosinaemia type 1, which has coagulopathy and renal tubulopathy.

Why is "Serum ceruloplasmin with 24-hour urinary copper" not the answer?

Ceruloplasmin and urine copper test for Wilson disease, which does not present in early infancy.

What concept does this question test?

It tests Genetic and metabolic disorders: alpha-1 antitrypsin deficiency in Pediatrics. Confirmation is by serum level with Pi phenotype or genotype. Lung disease follows later in life.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Genetic and metabolic disorders: alpha-1 antitrypsin deficiency?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.