Which syndrome is characterized by a child being highly sensitive to noise and having difficulty regulating anxiety?

Asperger's Syndrome, a condition on the autism spectrum, is indeed characterized by a range of sensory sensitivities, including heightened sensitivity to noise. Children with Asperger's may experience anxiety and find it challenging to regulate their emotional responses, particularly in overwhelming sensory environments. This can manifest as an increased sensitivity to sounds, which may lead to discomfort or distress. Additionally, the difficulty in social interactions and understanding social cues commonly associated with Asperger's can contribute to anxiety levels.

In contrast, other conditions listed do not typically emphasize auditory sensitivity or anxiety regulation as prominent features. Down Syndrome is primarily associated with cognitive and physical developmental delays. Turner's Syndrome affects physical development and is linked to other health issues, rather than sensory processing. Reye's Syndrome is a serious illness involving liver and brain damage, and it does not relate to auditory sensitivity or anxiety traits. Thus, Asperger's Syndrome is the most fitting condition for the characteristics described in the question.