HYPEREXPLEXIA AND STIFF-BABY SYNDROME - AN IDENTICAL NEUROLOGICAL DISORDER

Hyperekplexia (startle disease) is an unusual, familial, neurological disorder characterized by abnormally enhanced startle response, follow ed in most cases by momentary generalized muscular stiffness. These at tacks may cause the patients to fall rigidly, while remaining fully co nscious. Startle symptomatology has generally an onset in infancy and is often accompanied, during the first years of life, by rigidity, sle ep myoclonus, motor delay, regurgitation and apneic spells, which may cause sudden death. Stiff-baby syndrome is a familial disorder charact erized by marked rigidity, with neonatal onset and gradual reduction d uring infancy, regurgitations, motor delay and attacks of stiffness. W e report 4 new cases of hyperekplexia from two different families and another infant with stiff-baby syndrome discussing clinical, electroph ysiological and genetic aspects of both neurological disorders in rela tion to other reported cases. We suggest a continuum between these fam ilial syndromes, which are often misinterpreted as epilepsy or other d isorders.