Autism Spectrum Disorders include all but which of the following?

Autism Spectrum Disorders (ASDs) encompass a range of conditions characterized by challenges with social skills, repetitive behaviors, and communication difficulties. The correct choice is muscular dystrophy, which is a separate genetic disorder affecting muscle strength and function, rather than a neurodevelopmental disorder like those on the autism spectrum.

Asperger syndrome, Rett syndrome, and childhood disintegrative disorder are all classified under the umbrella of ASDs. Asperger syndrome is characterized by difficulty in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior and interests. Rett syndrome is primarily seen in girls and leads to a loss of purposeful hand skills and spoken language, alongside other symptoms. Childhood disintegrative disorder involves a significant regression in development after normal development during the first two years of life. In contrast, muscular dystrophy does not affect social or communication skills, as its primary impact is on physical capabilities. Thus, it does not belong among the conditions classified as Autism Spectrum Disorders.