Genetics: Angelman syndrome: 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 · Genetics: Angelman syndrome

Sample item

A child has severe developmental delay, absent speech, ataxic gait, seizures and frequent inappropriate laughter. Which gene is involved?

AFBN1BSMN1CMECP2DUBE3A on maternal chromosome 15

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

The answer and the reasoning

D. UBE3A on maternal chromosome 15

Angelman syndrome (happy puppet) arises from loss of the maternal UBE3A allele on 15q11-13 due to deletion, paternal UBD, imprinting defect or a UBE3A mutation. Features include a happy demeanour, microcephaly and EEG with large-amplitude slow waves. It is distinguished from Prader-Willi syndrome by parent of origin.

Option by option

A. FBN1
FBN1 mutation causes Marfan syndrome.
B. SMN1
SMN1 deletion causes spinal muscular atrophy.
C. MECP2
MECP2 mutation causes Rett syndrome.
D. UBE3A on maternal chromosome 15 (correct)
Correct. Maternal UBE3A loss causes Angelman syndrome.

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 D, UBE3A on maternal chromosome 15. Angelman syndrome (happy puppet) arises from loss of the maternal UBE3A allele on 15q11-13 due to deletion, paternal UBD, imprinting defect or a UBE3A mutation.

Why is "FBN1" not the answer?

FBN1 mutation causes Marfan syndrome.

Why is "SMN1" not the answer?

SMN1 deletion causes spinal muscular atrophy.

Why is "MECP2" not the answer?

MECP2 mutation causes Rett syndrome.

What concept does this question test?

It tests Genetics: Angelman syndrome in Pediatrics. Features include a happy demeanour, microcephaly and EEG with large-amplitude slow waves. It is distinguished from Prader-Willi syndrome by parent of origin.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Genetics: Angelman syndrome?

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.