A nurse is caring for a 3-year-old child with Down Syndrome. Which clinical manifestations should the nurse recognize as associated with Down Syndrome? (SELECT ALL THAT APPLY)

A. Atlantoaxial instability is a condition that can occur in children with Down syndrome, where the upper spine is less stable, leading to potential neurological complications. B. Normal developmental milestones are typically delayed in children with Down syndrome, making this option incorrect. C. Congenital hypothyroidism is common in children with Down syndrome, and thyroid function should be regularly monitored. D. Children with Down syndrome are at higher risk for frequent respiratory infections due to an altered immune system and other factors. E. Congenital heart defects are present in a significant number of children with Down syndrome, making this a key clinical manifestation.