NCIt definition : A pediatric disorder characterized by normal development for at least the first two
years of life followed by a severe regression in language, social interaction, bowel
or bladder control, and/or motor skills. The affected individual may also exhibit
repetitive and stereotyped patterns of behavior similar to autism.;
Alternative definition : NICHD: A neurodevelopmental disorder that presents between the ages of two and ten,
and is characterized by severe regression of communication, social interactions, bowel
or bladder control, and/or motor skills that has previously developed normally.;