Rinsho Shinkeigaku (Clinical Neurology)

Case Report

A pedigree of hereditary hyperekplexia

Hideyuki Moriyoshi, M.D.1)2), Yukiko Hata, Ph.D.3), Ryosuke Inagaki, M.D.1), Junichiro Suzuki, M.D., Ph.D.1), Suguru Nishida, M.D.1), Naoki Nishida, M.D., Ph.D.3) and Yasuhiro Ito, M.D., Ph.D.1)

1)Department of Neurology, TOYOTA Memorial Hospital
2)Present Address: Department of Neurology, Nagoya University Graduate School of Medicine
3)Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama

A 31-year old women presented with excessive startle reflex and frequent falls. Her startle reflex is induced by slight stimuli which are not problematic in most people. Soon after her startle reflex is evoked, generalized muscle stiffness occurs. She becomes rigid and falls down without loss of consciousness. Because she cannot protect herself when she is startled and falls, she has repeatedly bruised her head and face. The pedigree includes her father and two sisters with similar symptoms. Gene analysis revealed GLRA1 mutation, and she was diagnosed with hereditary hyperekplexia (HPX). Symptoms improved with clonazepam 1 mg/day. HPX patients live with severe anxiety about frequent falls and sometimes suffer serious injury, such as cerebral concussion or bone fracture. Although HPX might sometimes be underestimated, accurate diagnosis is very important for effective treatment.
Movie legends
Exaggerated startle reflex. Exaggerated startle reflex and generalized muscle contraction are induced by acoustic stimuli.
Full Text of this Article in Japanese PDF (641K)

(CLINICA NEUROL, 58: 435|439, 2018)
key words: Hyperekplexia, Startle disease, Glycine receptor, GLRA1, Fall

(Received: 26-Dec-17)