Acute Werdnig-Hoffmann disease, the most common cause of hypotonic infants, is progressive degenerative disease of anterior spinal neuron, and characterized by flaccid paralysis of extremities and fasciculation of tongue.

We experienced 3 cases of Werding-Hoffmann disease confirmed by electrodiagnostic examination and muscle biopsy.

They revealed generalized hypotonia with frog leg position, fasciculation of tongue, decreased or absent deep tendon reflexes without pathologic reflexes suggesting upper motor neuron diseases.

The clinical manifestations, values of laboratory examination including electrodiagnostic examination and muscle biopsy for diagnosis and differential diagnosis of Werding-Hoffmann disease were reviewed.