Which condition is associated with a single transverse palmar crease (Simian crease)?

Which condition is associated with a single transverse palmar crease (Simian crease)?

• A. Turner syndrome
• B. Klinefelter syndrome
• C. Down syndrome
• D. Patau syndrome

Answer: (C)

A single transverse palmar crease, or simian crease, is a clue often seen in Down syndrome. This crease runs horizontally across the palm as one line instead of the usual two creases, and it appears more frequently in individuals with trisomy 21 than in the general population. While not diagnostic by itself, its presence raises suspicion for Down syndrome when found alongside other typical signs such as hypotonia, flat facial profile, upslanting eyes, and potential congenital heart defects. The other conditions listed have distinct features that don’t commonly include a simian crease, so this finding most strongly points toward Down syndrome.

A single transverse palmar crease, or simian crease, is a clue often seen in Down syndrome. This crease runs horizontally across the palm as one line instead of the usual two creases, and it appears more frequently in individuals with trisomy 21 than in the general population. While not diagnostic by itself, its presence raises suspicion for Down syndrome when found alongside other typical signs such as hypotonia, flat facial profile, upslanting eyes, and potential congenital heart defects. The other conditions listed have distinct features that don’t commonly include a simian crease, so this finding most strongly points toward Down syndrome.