• Delayed developmental milestones and speech
• Behavioral disorders, such as ASD, ADD, anxiety, aggression, and depression
• Intellectual disability or learning problems (~100% of males, ~60% of females)
• Medical features including seizures, strabismus, scoliosis, and heart murmurs
• Physical characteristics, which are variable and may become more apparent over time, such as a long face, prominent forehead, large ears, and macro‐orchidism