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Updated: Mar 19, 2026

In Vivo Electrophysiological Measurement of Compound Muscle Action Potential from the Forelimbs in Mouse Models of Motor Neuron Degeneration
Published on: June 15, 2018
Motor neuropathy contributes to crouching in patients with Dravet syndrome
Cyril Gitiaux1, Nicole Chemaly2, Susana Quijano-Roy2
1From the Departments of Pediatric Neurology (C.G., N.C., C.B., I.D., M.H., C.C., R.N.) and Pediatric Neurophysiology (C.G., N.C., S.Q.-R.), and Reference Center for Rare Epilepsies (N.C., C.C., O.D., R.N.), Necker Enfants Malades Hospital, APHP, Paris; INSERM U1129-Infantile Epilepsies and Brain Plasticity (N.C., C.C., O.D., R.N.), Paris; Paris Descartes (N.C., C.C., O.D., R.N.), Sorbonne Paris Cité University; CEA (N.C., C.C., O.D., R.N.), Gif sur Yvette; Department of Pediatric Neurology (S.Q.-R.), Raymond Poincaré Hospital, APHP, Garches; and Paris Descartes University (C.G., I.D., R.N.), France. cyril.gitiaux@aphp.fr.
Objective:
Since SCN1A is expressed in the motor neuron initial segment, we explored whether motor neuron dysfunction could contribute to gait disturbance and orthopedic misalignment in patients with Dravet syndrome due to SCN1A mutations.
Methods:
We assessed 12 consecutive patients who presented to our institution between January and March 2013. All of them were older than 2 years and were positive for the SCN1A mutation. We performed nerve conduction velocity studies and needle EMG recordings.
Results:
We included 4 females and 8 males aged 2 to 17 years (median 7.5 years). All 12 patients showed gait disturbance regardless of age. Tendon reflexes were decreased in 4 of 12 patients. None presented cerebellar signs such as tremor, dysmetria, or adiadochokinesia. Nerve conduction study was normal or nearly normal in all patients, but EMG showed features of chronic denervation. Motor neuropathy/neuronopathy was definite in 7 patients and probable in 3.
Conclusions:
SCN1A mutations may alter axonal function, causing motor neuropathy/neuronopathy. This may contribute to gait disturbance and orthopedic misalignment, which is characteristic of patients with Dravet syndrome.
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