Childhood Disintegrative Disorder

Childhood disintegrative disorder is a condition which displays itself at 3 and 4 years of age on children who have typical development until age 2. Over several months, a child with this childhood disintegrative disorder will regress in academic, social, and language functioning from previously typical behavior. Childhood disintegrative disorder is associated with severe cognitive impairment. Behavioral features of autistic disorder must be present in at least two of the following areas: inability to interact socially, incapable of communicating needs, prefers solitary play; restricted repetitive and stereotyped features in behavior. A loss of skills may occur in two of the following areas: expressive or receptive language, social skills and/or flexible behavior, bowel or bladder control, play, or motor skills.
Mayo Clinic