Expanding the Phenotype and Genetic Defects Associated with the GOSR 2 Gene

Background The homozygous missense mutation c.430G>T (p.G144W) in the GOSR 2 gene has been repeatedly shown to cause progressive myoclonus epilepsy/ataxia. Thus far, no other disease associated GOSR 2 mutation has been reported. Methods From epilepsy, movement disorder and genetic clinics 43 patients suffering from progressive myoclonus epilepsy/ataxia were screened for defects in GOSR 2, SCARB 2 and CSTB . Results A 61‐year‐old female patient suffering from progressive myoclonus epilepsy was found to be compound heterozygous for the known c.430G>T and a novel c.491_493del AGA (p.K164del) GOSR 2 mutation. This is so far the oldest GOSR 2 patient and her disease course seems overall milder. Conclusions This finding further highlights the GOSR 2 gene as a cause of progressive myoclonus epilepsy and expands the genotype for a potentially weaker disease allele.