Pedigree analysis · USMLE Step 1

A pedigree shows only males affected in multiple generations, and no daughters are affected even when fathers are affected. Which pattern is the best fit?

  1. Autosomal dominant
  2. X-linked recessive
  3. X-linked dominant
  4. Autosomal recessive
Show answer and explanation

Correct answer: X-linked recessive

When only males are affected across generations and no daughters are affected even from affected fathers, X-linked recessive inheritance is the best fit.

Difficulty: Medium Question 16 of 19

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