A family report described reduced startle symptoms with clonazepam despite a severe neonatal syndrome that remained fatal.
The unusual family phenotype
The report described six newborns from a consanguineous Saudi Arabian kindred with severe hyperekplexia, microcephaly, simplified cerebral folding, and cerebellar underdevelopment. Their EEGs were reported as normal. The children responded symptomatically to clonazepam, yet all died within six weeks.
DNA was available from two patients. The overlapping regions of homozygosity did not contain the known hyperekplexia genes considered by the investigators. The authors proposed a distinct recessive syndrome rather than identifying a confirmed causative gene.
Response does not establish disease modification
Improvement in startle or stiffness is a different outcome from reversal of structural brain abnormalities or prevention of death. The report cannot show that clonazepam caused or prevented the fatal outcome, and its small related group does not define prognosis for ordinary hyperekplexia.
For interpretation, distinguish a non-epileptic startle disorder from seizures, and identify the specific symptom being treated. A benzodiazepine response is not by itself a diagnostic test. This report is valuable precisely because symptomatic responsiveness coexisted with a much broader and more severe clinical course.
Source paper
Original analysis of the supplied journal article, identified as PMC3488335.
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