Heller’s syndrome is characterized by regression of milestones after _________
**Core Concept**
Heller's syndrome, also known as childhood disintegrative disorder, is a rare neurodevelopmental disorder characterized by significant regression of previously acquired skills and behaviors in children who had initially developed normally. This regression typically occurs after a period of normal development, often between the ages of 2 and 4 years.
**Why the Correct Answer is Right**
The correct answer is **12 to 48 months**. This regression is often preceded by a period of normal development, during which the child may have achieved language, social, and adaptive skills. However, between 12 and 48 months of age, there is a sudden and significant decline in these skills, leading to severe impairments in communication, social interaction, and adaptive behavior. This regression is thought to be related to an underlying neurodevelopmental disorder, such as autism spectrum disorder or tuberous sclerosis complex.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a time period and is too vague. Heller's syndrome is characterized by a specific age range of regression.
**Option B:** This option is incorrect because it is not supported by scientific evidence. While some children with autism spectrum disorder may experience regression, Heller's syndrome is a distinct clinical entity with a specific age range of regression.
**Option C:** This option is incorrect because it is too broad and does not specify a time period. Regression can occur at any age, but Heller's syndrome is characterized by regression between 12 and 48 months.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Heller's syndrome is a rare and distinct clinical entity from autism spectrum disorder. A thorough diagnostic evaluation is necessary to rule out other underlying causes of regression.
**Correct Answer:** D.