What is the typical onset age for Childhood Disintegrative Disorder?

Childhood Disintegrative Disorder (CDD), also known as Heller's syndrome, typically manifests after a period of normal development, making the onset age particularly significant. The disorder is characterized by the loss of previously acquired skills in areas such as language, social interactions, and motor functions, typically occurring between the ages of 2 and 10. It is important to note that while skills are lost, the most common onset occurs around the ages of 3 to 4. Recognizing these symptoms and their onset is critical for timely intervention and support for affected individuals.

Choosing "by age 10" aligns with the understanding that while the disorder begins in early childhood, the specific timeframe for the symptoms to emerge often falls within this range. The other options suggest onset at either too early an age or too late, which does not accurately reflect the typical developmental timeline for CDD.