GLRA1 and hyperekplexia: Both sisters exhibited frequent startles during NREM sleep, a phenotype previously described in early reports of hyperekplexia without identification of GLRA1 gene mutations.6, 7 During N3 sleep, spontaneous startles were associated with sleep terrors and persistent slow postarousal EEG activity, a pattern typically observed in disorders of arousal (DOA),12 these parasomnias being previously reported in hyperekplexia patients.