What is the inheritance pattern of HBOC and Lynch syndrome, and what does this imply for first-degree relatives?

What is the inheritance pattern of HBOC and Lynch syndrome, and what does this imply for first-degree relatives?

• A. Autosomal recessive
• B. X-linked
• C. Autosomal dominant
• D. Mitochondrial

Answer: (A)

HBOC and Lynch syndrome are inherited in an autosomal dominant fashion. This means a single mutated copy of the relevant gene is enough to increase cancer risk. Because of this pattern, each first-degree relative (parent, child, or full sibling) of an affected person has a 50% chance of carrying the pathogenic variant. This makes family-based testing important: if a relative carries the mutation, they can pursue targeted surveillance and risk-reducing options; if they do not carry it, their inherited risk from these mutations is not elevated.

HBOC and Lynch syndrome are inherited in an autosomal dominant fashion. This means a single mutated copy of the relevant gene is enough to increase cancer risk. Because of this pattern, each first-degree relative (parent, child, or full sibling) of an affected person has a 50% chance of carrying the pathogenic variant. This makes family-based testing important: if a relative carries the mutation, they can pursue targeted surveillance and risk-reducing options; if they do not carry it, their inherited risk from these mutations is not elevated.