GNAO1 mutation-related severe involuntary movements treated with gabapentin

Background: Mutations in GNAO1 typically result in neurodevelopmental disorders, including involuntary movements. They may be improved using calcium-channel modulators. Case: The patient visited our hospital at age 2 years because of moderate global developmental delay. Her intermittent, generalized involuntary movements started at age 8 years. A de novo GNAO1 mutation, NM_020988.2:c.626G > A, (p.Arg209Cys), was identified by whole exome sequencing. At age 9 years, she experienced severe, intermittent involuntary movements, which led to rhabdomyolysis. She needed intensive care with administration of midazolam, dantrolene sodium hydrate, and plasma exchange. We started treating her with gabapentin (GBP), after which she recovered completely. At age 11 years, she developed continuous, generalized involuntary movements. This prompted us to increase the GBP dose, which again resolved the involuntary movements completely. Conclusion: In the case of movement disorders associated with GNAO1 mutations, GBP treatment may be attempted before more invasive procedures are performed.