CASE #2 A parent brings in her 1-year-old daughter, Sara. She is concerned because Sara hasn’t begun speaking yet and has difficulty interacting with others. She still has the startle reflex. She can't make eye contact with other people. On a physical exam, the doctors notices she has a spot on her eye. What birth defect does Sara most likely have? Which one?

Tay-Sach's disease
Muscular Dystrophy
Down Syndrome