Embryology: retinoid teratogenicity: practice question

A Anatomy 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.

Try it

Anatomy · Embryology: retinoid teratogenicity

Sample item

A newborn has anotia, micrognathia, a conotruncal heart defect and a small thymus. The mother took a drug for severe cystic acne during the first trimester. Which drug is the likely teratogen?

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

The answer and the reasoning

B. Isotretinoin

Retinoids such as isotretinoin disturb neural crest cell migration, causing craniofacial (ear and jaw), conotruncal cardiac, thymic and central nervous system defects. Women taking them need reliable contraception.

Option by option

  • A. Lithium

    Lithium is linked with Ebstein anomaly of the tricuspid valve.

  • B. Isotretinoin (correct)

    Correct. Retinoid embryopathy affects neural crest derivatives, producing ear, jaw, heart and thymic defects.

  • C. Warfarin

    Warfarin embryopathy causes nasal hypoplasia and stippled epiphyses.

  • D. Phenytoin

    Phenytoin causes the fetal hydantoin syndrome, with digital hypoplasia and facial dysmorphism.

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.

More Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, Isotretinoin. Retinoids such as isotretinoin disturb neural crest cell migration, causing craniofacial (ear and jaw), conotruncal cardiac, thymic and central nervous system defects.

Why is "Lithium" not the answer?

Lithium is linked with Ebstein anomaly of the tricuspid valve.

Why is "Warfarin" not the answer?

Warfarin embryopathy causes nasal hypoplasia and stippled epiphyses.

Why is "Phenytoin" not the answer?

Phenytoin causes the fetal hydantoin syndrome, with digital hypoplasia and facial dysmorphism.

What concept does this question test?

It tests Embryology: retinoid teratogenicity in Anatomy. Women taking them need reliable contraception.

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 Embryology: retinoid teratogenicity?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.