Skip to Content


Pronunciation: hi'per-ek-plek'se-a

Definition: A hereditary disorder in which there are pathologic startle responses, protective reactions to unanticipated, potentially threatening, stimuli of any type, particularly auditory; the stimuli induce often widespread and violent sudden contractions of the head, neck, spinal, and sometimes, limb musculature, resulting in involuntary shouting, jerking, jumping, and falling; autosomal dominant and recessive inheritance forms, with the responsible gene localized to chromosome 5q; probably the result of lack of inhibitory neurotransmitters, glycine, or GABA.

Synonym(s): kok disease, startle disease

[hyper- + G. ekplexia, sudden shock, fr. ekplesso, to startle]

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.