Neonatal startle disease or stiff baby syndrome is a rare hereditary disease. It is often misdiagnosed as either neonatal seizure or cerebral palsy because of its characteristic exaggerated fits, which can be activated by external voice or touch. In fact, the exact diagnosis can be made easily according to the patient's family history and clinical examination at bedside. Glabellar tapping is a method to elicit the exaggerated responses, and the events can be relieved by forced knee-chest position. Herein, we report one case with hereditary startle disease accompanied with cyanosis and severe apneas, which could be relieved by forced knee-chest position and oral clonazepam. In conclusion, we suggest the diagnosis of the startle disease should be considered when newborns present the symptoms of neonatal seizure. Once the disease is noticed, we can pursue a simple method to confirm the diagnosis at bedside and unnecessary examination like magnetic resonance imaging can be avoided.
