Familial Hyperekplexia and Refractory Status Epilepticus: A New Autosomal Recessive Syndrome

Abstract

Hyperekplexia is a rare disorder characterized by an exaggerated startle response to noise and handling and by neonatal hypertonia. It is predominantly an autosomal dominant disease; however, atypical cases with additional variable manifestations have been reported. We report a hitherto undescribed association of hyperekplexia and refractory status epilepticus in two siblings. Both children were born after an uneventful pregnancy to healthy unrelated Ashkenazi Jews. Both had increased startle and tone from birth and later became hypotonic. A metabolic evaluation, including a muscle biopsy, was normal. At the age of 18 months and 12 months, respectively, they developed status epilepticus refractory to all treatment that culminated in death. An autopsy in the girl did not reveal any brain pathology. The unusual association of hyperekplexia and refractory status epilepticus in both children suggests that this is a new autosomal recessive syndrome, possibly a channelopathy affecting both the brain and the spinal cord.