What age range marks the onset of Childhood Disintegrative Disorder?

Childhood Disintegrative Disorder, also known as Heller's syndrome, is characterized by a significant regression in multiple areas of functioning after a period of normal development. The disorder typically manifests between the ages of 2 and 10 years.

This is crucial because the diagnosis involves observing a child who has initially developed skills in communication, social interaction, and play, only to experience a severe loss of these skills. The regression must occur after at least two years of normal development. This timeline places the onset firmly in the range of 2 to 10 years, highlighting that the child must progress through early childhood before significant disintegration of their abilities can be recognized.

Other age ranges do not align with the clinical presentation of Childhood Disintegrative Disorder. For example, the onset before 1 year would not be applicable, as it is primarily after this period when typical developmental markers are established, making the behavioral regression identifiable.