What is hyperplexia?

Hyperplexia, also known as startle disease or hyperekplexia, is a rare neurological condition that causes exaggerated startle reflexes. People with hyperplexia experience sudden, brief, involuntary muscle contractions in response to unexpected stimuli, such as loud noises, bright lights, or sudden movements. These startle reactions can be very intense, causing the person to jump, flail their arms and legs, or even lose consciousness.

Hyperplexia is usually caused by a mutation in the GLRA1 gene, which encodes the glycine receptor alpha-1 subunit. This protein is involved in the transmission of signals in the brain and spinal cord, and the mutation affects the way that the brain processes sensory information.

The symptoms of hyperplexia can vary depending on the severity of the condition. In mild cases, people may experience only occasional startle reactions. In severe cases, people may have hundreds of startle reactions per day, which can significantly interfere with their daily activities.

Hyperplexia is usually diagnosed based on the person's symptoms and a physical examination. In some cases, genetic testing may be recommended to confirm the diagnosis.

Treatment for hyperplexia typically involves medication to reduce the severity of the startle reactions. Physical therapy may also be recommended to help people with hyperplexia manage their symptoms and improve their quality of life.