<unk>  is when a child who has reached a certain developmental stage begins to lose previously acquired milestones. It differs from developmental delay in that a child experiencing developmental delay is either not reaching developmental milestones or not progressing to new developmental milestones, while a child experiencing<unk>  will lose milestones and skills after acquiring them.<unk>  is associated with diagnoses of autism spectrum disorder, childhood disintegrative disorder, Rett syndrome, Landau-Kleffner syndrome, and neuro-degenerative diseases. The loss of motor, language, and social skills can be treated with occupational therapy, physical therapy, and speech therapy.
Developmental regression
Neuronal migration disorder
Developmental disorder
Fetal alcohol spectrum disorder
Neurodevelopmental disorder
Specific developmental disorder
Child abuse
Sexual maturation disorder