Hyperekplexia - epilepsy

Hyperekplexia /ˌhaɪ.pɚ.ɛkˈplɛk.si.ə/ ("exaggerated surprise") is a very rare neurologic disorder classically characterised by pronounced startle responses to tactile or acoustic stimuli and hypertonia. The hypertonia may be predominantly truncal, attenuated during sleep and less prominent after a year of age. [Source: Wikipedia ]

OrphaNet reference
Hyperekplexia - epilepsy 
May Cause
Epilepsy
Hyperekplexia