Background: The homozygous missense mutation c.430G>T (p.G144W) in the GOSR2 gene has been repeatedly shown to cause progressive myoclonus epilepsy/ataxia. Thus far, no other disease associated GOSR2 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 GOSR2, SCARB2 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_493delAGA (p.K164del) GOSR2 mutation. This is so far the oldest GOSR2 patient and her disease course seems overall milder.
Conclusions: This finding further highlights the GOSR2 gene as a cause of progressive myoclonus epilepsy and expands the genotype for a potentially weaker disease allele.
Keywords: GOSR2; ataxia; myoclonus; progressive myoclonus ataxia; progressive myoclonus epilepsy.