A disorder of infants and children with pathological startle response, features of other system involvement, falls, and stiffness with retained consciousness. It should be differentiated from conditions such as myoclonic epilepsy, psychogenic movement disorder, Isaac syndrome, Schwartz-Jampel syndrome, Gilles de la Tourette, and culture-specific startle syndromes such as jumping Frenchman of Maine. A 5-year-old child symptomatic with repeated falls spontaneously as well as by sound and activities since neonatal period. He was having hyperalert facies, intelligent, cooperative with mild dysmorphism. His investigations were noncontributory except giant somatosensory evoked potentials and skeletal abnormalities. He showed excellent response to clonazepam and no complications on withdrawing the antiepileptic drugs. Proper diagnosis is of great therapeutic relevance and is based on high degree of suspicion.
Keywords: Differential diagnosis; hyperekplexia plus; startle.