INTRODUCTION Hereditary hyperekplexia is a neurological disorder characterized by excessive startle responses with violent jerking to noise or touch, stiffening of the trunk and limbs, clenching of the fists and attacks of a high-frequency trembling. Hyperekplexia has a heterogeneous genetic background with several identified causative genes and demonstrates both dominant and recessive inherita...

Startle disease or hereditary hyperekplexia has been shown to result from mutations in the alpha1-subunit gene of the inhibitory glycine receptor (GlyR). In hyperekplexia patients, neuromotor symptoms generally become apparent at birth, improve with age, and often disappear in adulthood. Loss-of-function mutations of GlyR alpha or beta-subunits in mice show rather severe neuromotor phenotypes. ...

The effect of posture on the EMG pattern of the normal auditory startle reflex was investigated. The startle response to an unexpected auditory tone was studied in eleven normal subjects when standing, and in six normal subjects when sitting relaxed or tonically plantar flexing both feet. Reflex EMG activity was recorded in the tibialis anterior and soleus about twice as frequently when standin...

Startle is a basic alerting reaction common to all mammals. A rapid reflex not amenable to voluntary control, it was studied extensively by Strauss in 1929 [1], and is the subject of a monograph by Landis and Hunt [2] and a more recent study by Gogan [3]. In the human adult, except for minor interpersonal variations, a stereotyped motor pattern is seen consisting of eye blinking facial grimacin...

We used proton magnetic resonance spectroscopic imaging (MRSI) to assess in vivo cortical neuronal involvement in hyperekplexia. Cerebral neuronal function was measured using proton MRSI in four unrelated patients with hyperekplexia and 20 healthy controls. All patients had the major form of hyperekplexia, with additional atypical clinical features in two of them. Family history was positive in...

The last few years have seen remarkable developments in our understanding of the physiology, pharmacology and genetics of inhibitory glycinergic synapses. In part, this has been due to the development of new resources such as specific antisera recognizing glycine receptor (GlyR) and transporter (GlyT) subtypes, but also the characterization of new mouse, zebrafish and bovine genetic models of g...

BACKGROUND AND OBJECTIVES Hyperekplexia and the stiff-man syndrome (SMS) are both conditions with exaggerated startle suggesting abnormal brainstem function. Investigation of brainstem reflexes may provide insight into disturbed reflex excitation and inhibition underlying these movement disorders. PATIENTS AND METHODS Using four-channel EMG, we examined four trigeminal brainstem reflexes (mon...

Two sisters aged 12 and 13 applied to our hospital with complaints of jerking tonic contraction triggered by sudden noise. Diffuse bilaterally polyspike-wave discharges appeared on waking electroencephalography and during that time a startle-induced tonic contraction was seen. Their neurological examinations and neuro-radiological imaging were normal except for hyperreflexia. We presented these...

The glycine transporter subtype 2 (GlyT2) is localized in the axon terminals of glycinergic neurons. Mice deficient in GlyT2 are normal at birth but during the second postnatal week develop a lethal neuromotor deficiency that resembles severe forms of human hyperekplexia (hereditary startle disease) and is characterized by spasticity, tremor, and an inability to right. Histological and immunolo...