Abstract: Objective　To investigate the clinical and genetic features of hyperekplexi caused by GLRA1 gene mutation. Methods　The clinical data of hyperekplexi in a child admitted in July 2019 were retrospectively analyzed. Results　There was a boy aged two months and 29 days. Since the neonatal period, the child has developed an excessive startle response such as generalized stiffness and hypertonia to sudden external stimuli. Physical examination exhibited the positive nose-tapping reflex. There were no obvious abnormalities in laboratory tests, electroencephalogram (EEG) and neuroimaging tests. The whole exome sequencing confirmed the heterozygous missense mutation, (NM_000171.3), c.920A>G, in GLRA1 gene. The mutation was not found in either parent, and it was a novo mutation. The missense mutation has not been reported internationally and is suspected to be pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines. After oral treatment with clonazepam, the symptoms of the child were significantly improved, but the muscle tension of the limbs was still high. Conclusion　The hyperekplexia was confirmed in a child due to a mutation in the GLRA1 gene. Genetic analysis could help in early diagnosis and treatment.

Key words: GLRA1 gene;　mutation;　hyperekplexia