Hereditary Hyperekplexia Overview
Learn About Hereditary Hyperekplexia
Hereditary hyperekplexia is a condition in which affected infants have increased muscle tone (hypertonia) and an exaggerated startle reaction to unexpected stimuli, especially loud noises. Following the startle reaction, infants experience a brief period in which they are very rigid and unable to move. During these rigid periods, some infants stop breathing, which, if prolonged, can be fatal. Infants with hereditary hyperekplexia have hypertonia at all times, except when they are sleeping.
Mutations in multiple genes have been found to cause hereditary hyperekplexia. Most of these genes provide instructions for producing proteins that are found in nerve cells (neurons). These proteins are involved in the response of neurons to a molecule called glycine. This molecule is an amino acid, which is a building block of proteins. Glycine also acts as a neurotransmitter, which is a chemical messenger that transmits signals in the nervous system. Gene mutations that cause hereditary hyperekplexia disrupt normal glycine signaling in neurons in the spinal cord and the part of the brain that is connected to the spinal cord (the brainstem). Abnormal signaling in neurons in the brain and neurons that send signals to muscles throughout the body result in abnormal muscle movements, exaggerated startle reaction, and other symptoms characteristic of this disorder.
The exact prevalence of hereditary hyperekplexia is unknown. This condition has been identified in more than 150 individuals worldwide.
Hereditary hyperekplexia has different inheritance patterns.
Texas Childrens Physician Group
Mered Parnes is a Pediatric Neurologist and a Pediatrics provider in Austin, Texas. Dr. Parnes and is rated as an Advanced provider by MediFind in the treatment of Hereditary Hyperekplexia. His top areas of expertise are Drug Induced Dyskinesia, Chorea, Opisthotonos, Hereditary Hyperekplexia, and Deep Brain Stimulation. Dr. Parnes is currently accepting new patients.
Chaya Murali is a Pediatrics specialist and a Medical Genetics provider in Houston, Texas. Dr. Murali and is rated as an Advanced provider by MediFind in the treatment of Hereditary Hyperekplexia. Her top areas of expertise are Hereditary Hyperekplexia, Osteogenesis Imperfecta, Deafness Craniofacial Syndrome, Retinopathy Pigmentary Mental Retardation, and Myringotomy. Dr. Murali is currently accepting new patients.
Lindsay Burrage is a Medical Genetics specialist and a Pediatrics provider in Houston, Texas. Dr. Burrage and is rated as an Advanced provider by MediFind in the treatment of Hereditary Hyperekplexia. Her top areas of expertise are Urea Cycle Disorders (UCD), Hypotonia, Argininosuccinic Aciduria, and Microcephaly. Dr. Burrage is currently accepting new patients.
Summary: Newborn screening (NBS) is a global initiative of systematic testing at birth to identify babies with pre-defined severe but treatable conditions. With a simple blood test, rare genetic conditions can be easily detected, and the early start of transformative treatment will help avoid severe disabilities and increase the quality of life. Baby Detect Project is an innovative NBS program using a pane...
Summary: Hereditary hyperekplexia is a rare neuronal disorder, caused by genetic defects leading to dysfunction of glycinergic neurotransmission. The clinical presentation is characterized by stiffness and exaggerated startle responses to unexpected stimuli, that appear shortly after birth. The generalised stiffness can lead to apnea and sudden infant death syndrome. Several genes are known to be associate...
Published Date: May 01, 2018
Published By: National Institutes of Health