Child Disintegrtive Disorder

"Childhood disintegrative disorder is a condition in which young children develop normally until age 3 or 4, but then demonstrate a severe loss of social, communication and other skills."

"Doctors sometimes confuse this rare disorder with late-onset autism because both conditions involve normal development followed by significant loss of language, social, play and motor skills. However, autism typically occurs at an earlier age. There's also a more dramatic loss of skills in children with childhood disintegrative disorder and a greater likelihood of mental retardation. In addition, childhood disintegrative disorder is far less common than autism."