Genetic and metabolic disorders: inheritance patterns: 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: inheritance patterns

Sample item

Which statement about inheritance patterns is correct?

AX-linked recessive disease passes from father to sonBMitochondrial disease passes from fathers to all offspringCMitochondrial disorders are transmitted through the mother; trinucleotide repeat disorders show anticipationDAnticipation is typical of autosomal recessive metabolic disease

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

The answer and the reasoning

C. Mitochondrial disorders are transmitted through the mother; trinucleotide repeat disorders show anticipation

Mitochondrial DNA is inherited from the oocyte and so passes from the mother to all children. Trinucleotide repeat expansions, such as fragile X and Huntington disease, can worsen in successive generations, a phenomenon called anticipation.

Option by option

A. X-linked recessive disease passes from father to son
X-linked recessive traits cannot pass from father to son.
B. Mitochondrial disease passes from fathers to all offspring
Fathers do not transmit mitochondrial DNA.
C. Mitochondrial disorders are transmitted through the mother; trinucleotide repeat disorders show anticipation (correct)
Correct. Both statements are true.
D. Anticipation is typical of autosomal recessive metabolic disease
Anticipation is not typical of recessive enzyme defects.

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, Mitochondrial disorders are transmitted through the mother; trinucleotide repeat disorders show anticipation. Mitochondrial DNA is inherited from the oocyte and so passes from the mother to all children.

Why is "X-linked recessive disease passes from father to son" not the answer?

X-linked recessive traits cannot pass from father to son.

Why is "Mitochondrial disease passes from fathers to all offspring" not the answer?

Fathers do not transmit mitochondrial DNA.

Why is "Anticipation is typical of autosomal recessive metabolic disease" not the answer?

Anticipation is not typical of recessive enzyme defects.

What concept does this question test?

It tests Genetic and metabolic disorders: inheritance patterns in Pediatrics. Trinucleotide repeat expansions, such as fragile X and Huntington disease, can worsen in successive generations, a phenomenon called anticipation.

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 Genetic and metabolic disorders: inheritance patterns?

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.