Which of the following is a characteristic of Down syndrome?

Choice A rationale Down syndrome (Trisomy 21) is a chromosomal disorder characterized by the presence of an extra copy of chromosome 21. A highly characteristic musculoskeletal feature is hypotonia, or poor (diminished) muscle tone, rather than enhanced tone. Hypotonia contributes to developmental delays and can affect feeding and posture. Enhanced muscle tone (hypertonia) is a finding associated with other conditions, like cerebral palsy or some neurological insults. Choice B rationale The Simian crease, or single transverse palmar crease, is a distinct feature found in approximately 50. Choice C rationale High muscle tone (hypertonia) is the opposite of what is typically observed in clients with Down syndrome. Hypotonia (low muscle tone) is a hallmark sign, often contributing to the characteristic posture and delayed acquisition of motor milestones. Hypertonia, which represents increased resistance to passive muscle stretch, is generally inconsistent with the phenotype of Trisomy 21. Choice D rationale Normal muscle tone is not a characteristic of Down syndrome. Individuals with this condition almost universally exhibit some degree of hypotonia, often quite pronounced. This low muscle tone is a major contributing factor to the developmental and physical challenges experienced. Therefore, classifying their muscle tone as "normal" is scientifically inaccurate regarding the typical phenotype of Trisomy 21.