A recent large genotype–phenotype study in PMS has suggested that there is no statistically significant difference in prevalence of epilepsy when comparing those with sequence variants and Class 1 deletions (deletions including only SHANK3 or SHANK3 in combination with ARSA and/or ACR and RABL2B) versus those with Class 2 deletions (all other deletions). Here, SHANK3 is linked to epilepsy.