What is a significant characteristic of Childhood Disintegrative Disorder?

Childhood Disintegrative Disorder, also known as Heller's syndrome, is characterized by a significant and profound regression in multiple areas of functioning after a period of at least two years of normal development. This regression can manifest across various domains, including language, social skills, and motor skills.

Children with this disorder typically exhibit a loss of previously acquired skills, leading to challenges in communication, social interaction, and everyday functioning. The severity of these regressions can deeply impact a child's ability to engage with their environment and peers.

The other options describe characteristics that do not align with the core features of Childhood Disintegrative Disorder. For example, onset by age 5 is incorrect because the disorder typically occurs after a minimum of two years of normal development, often recognized between the ages of 2 and 4. Improvement in social skills contradicts the nature of the disorder, as individuals do not show improvement but rather a decline in their social abilities. Lastly, a diagnosis commonly occurring after age 10 does not reflect the typical age range for the onset of the disorder, as it is usually diagnosed much earlier.