A patient's condition affects both males and females and is transmitted from affected mothers and fathers to children of both sexes. This disease could follow any of the following inheritance patterns EXCEPT one. Which is the EXCEPTION?

Correct answer: A. Y-linked

• A. CORRECT — this is the EXCEPTION. Y-LINKED (holandric) inheritance passes only from FATHER TO SON, since only males carry a Y chromosome. Females can never be affected or be carriers, so a disorder appearing in both sexes cannot be Y-linked.
• B. Autosomal dominant conditions affect both sexes equally with vertical transmission through generations — compatible.
• C. X-linked conditions do affect both sexes (recessive forms predominantly males, dominant forms both), so this pattern is not excluded.
• D. Autosomal recessive conditions affect males and females equally and can appear in the offspring of two unaffected carrier parents — compatible with the description.