Enigma of autism regression mechanistic pathways, clinical phenotypes, and early intervention implications

Table 5 Clinical features and red flags in suspected autism regression

Feature	Typical ASD regression	Urgent red flags
Age of onset	18-24 months	< 12 months or > 36 months
Motor skills	Preserved walking, grasping)	Loss of coordination or motor milestones
Language	Loss of expressive language/babbling	Loss of receptive language
Course	Stable after initial regression	Progressive or fluctuating decline
Physical growth	Normal parameters	Head circumference deceleration, lethargy
Behavior	Social withdrawal	Frequent staring spells or suspected seizures

ASD: Autism spectrum disorder.