Table 3.

Early warnings signs in children at risk for ASD

Age (months)	Clinical presentation
6–12	• Reduced or limited smiles or other joyful expressions directed at people • Limited or no eye contact • Limited reciprocal sharing of sounds, smiles, or facial expressions • Diminished, atypical, or no babbling or gesturing (e.g., pointing, reaching, waving ‘bye-bye’) • Limited response to name when called
9–12	• Emerging repetitive behaviours (e.g., spinning or lining up objects) • Unusual play (e.g., intense visual or tactile exploration of toys)
12–18	• No single words • Absence of compensatory gestures (such as pointing) • Lack of pretend play • Limited joint attention (initiating, responding, sharing of interests)
15–24	• Diminished, atypical, or no spontaneous or meaningful two-word phrases
Any age	• Parental and other caregiver concerns about the possibility of ASD
Any age	• Developmental regression (loss of skills): reduced frequency or loss of social behaviours (e.g., directing eye gaze to others) and communication (words and gestures) relative to earlier age

Data drawn from references (20–24)

ASD Autism spectrum disorder.