True concerning the presence of a single palmar crease:

• A. Is always associated with Down syndrome
• B. Occurs unilaterally in 10% and bilaterally in 5% of newborn infants
• C. Has no clinical significance
• D. In combination with short fingers, incurved little finger, and low set thumb investigate Down syndrome

Answer: (D)

The single palmar crease is a non-specific newborn finding. It can appear in healthy infants and is not diagnostic for Down syndrome on its own, even though it’s more common in affected individuals. Its presence only becomes meaningful when it appears along with other subtle signs such as short fingers, an incurved little finger, and a low-set thumb. In that combination, it raises suspicion for Down syndrome and warrants appropriate screening and evaluation. The other statements aren’t accurate because the crease can occur in healthy babies, the unilateral/bilateral frequency figures aren’t reliable indicators, and claiming no significance ignores the value of this feature when it appears with other dysmorphic signs.