Acetazolamide-responsive episodic ataxia associated with a de novo SCN2A mutation Leach, Emma L.; van Karnebeek, Clara D. M.; Townsend, Katelin N.; Tarailo-Graovac, Maja; Hukin, Juliette; Gibson, William T.
Introduction: Episodic ataxia type 2 (EA2) is characterized by paroxysmal attacks of ataxia interspersed by asymptomatic periods. Dominant mutations or copy number variants in CACNA1A are a well-known cause of EA2. Clinical presentation: This boy presented clinical features of EA2, and also showed cerebellar atrophy, hypotonia, autism and global developmental delay at age 4 years. Acetazolamide prevented further episodes of ataxia. Extensive biochemical and genetic tests were unrevealing; whole exome sequencing found a previously unreported variant in SCN2A, proven to be de novo and predicted to be protein-damaging. Conclusion: Considered alongside a previous report of ataxia in an SCN2A mutation-positive patient, our case further illustrates the genetic heterogeneity of EA2 and suggests that acetazolamide may be an effective treatment in a broader range of channelopathy-related conditions.
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