MUTYH-associated polyposis is best described as which inheritance pattern, and what is the polyp presentation?

• A. X-linked with no polyps
• B. Autosomal recessive with numerous but fewer polyps
• C. Mitochondrial with polyp burden high
• D. Autosomal dominant with numerous polyps

Answer: (B)

MUTYH-associated polyposis comes from mutations in both copies of the MUTYH gene, so it is inherited in an autosomal recessive pattern. People with MAP typically develop multiple colorectal polyps, but the number is generally lower than in classic FAP, often ranging from around ten to a few hundred polyps rather than hundreds to thousands. This combination—recessive inheritance and a polyp burden that is substantial but not as extreme as in APC-associated FAP—best fits MUTYH-associated polyposis. The other inheritance patterns don’t match MAP: X-linked or mitochondrial patterns don’t align with how MAP is passed down, and autosomal dominant with very numerous polyps describes classic FAP rather than MAP.