Molecular mechanisms of inherited startle syndromes

Inherited neurological disorders involving an exaggerated startle response to unexpected sensory stimuli have been identified in mice, cows, dogs, horses and humans. Recent studies of the molecular pathology of a number of these startle syndromes have revealed that they are caused by defects in the inhibitory glycinergic pathways that mediate reciprocal and recurrent inhibition in the spinal cord. These defects arise from various mutations of the receptor for glycine, which either impair its sensitivity to agonists or reduce its expression in vivo. The emergent models of the molecular mechanisms that underlie startle disorders illustrate how diverse mutations can converge physiologically to produce a common phenotype.