Reviewing literature, severe mutations in MECP2 gene, such as large deletions, early truncating, and missense mutations in the methyl‐binding domain or the nuclear localizing segment seem to be associated with earlier or more sever epilepsy, whereas milder mutations such as late truncating or C‐terminal deletions seem to have a protective effect on epilepsy onset (Jian et al., 2006, 2007; Nectoux et al., 2008; Pintaudi et al., 2010). The gene discussed is MECP2; the disease is epilepsy.