What is a common feature observed in the hands of a person with Down syndrome?

Individuals with Down syndrome often exhibit a single palmar crease, also known as a simian line, as a common characteristic. This feature is due to genetic factors associated with the condition. The presence of a single palmar crease is notable because most individuals typically have two creases. This particular finding can be associated with various genetic conditions and is often used in clinical evaluations to identify individuals who may have chromosomal abnormalities.

While extra digits, long fingers, or webbed fingers can occur in some genetic disorders, they are not specifically characteristic of Down syndrome. Instead, the distinctive single palmar crease serves as a recognizable physical marker for this condition.