Hyperekplexia Associated With Apnea and Sudden Infant Death Syndrome

Stiff-baby syndrome or hyperekplexia (also known as startle disease) is an unusual familial neurologic disorder that may be associated with fatal apnea or an apparent life-threatening event in infancy. While the neonatal clinical features of increased muscle tone, pathologic startle response, and occasional myoclonic jerks have been reported,1the association of hyperekplexia with apnea and feeding difficulties has not been emphasized in the pediatric literature. The purpose of this report is to document further the association of sudden infant death syndrome (SIDS) and recurrent apnea of infancy with hyperekplexia, to describe possible common pathogenic mechanisms, and to summarize the response to myorelaxing therapy. In addition, we provide further evidence for assignment of the hyperekplexia gene to chromosome 5q. Patient Report. A white male infant (propositus) was born after an uncomplicated pregnancy and weighed 2683 g at birth. His Apgar score was 7/9 at 1 and 5 minutes. At birth,