Criteria for atypical Rett syndrome were fulfilled and MECP2 (MIM# 300005) gene sequencing revealed a known heterozygous pathogenic variant (c.316C>T, p.R106W), which accounts for ~4% of pathogenic variants in MECP2 (Neul et al., 2010; Webb & Latif, 2001). The gene discussed is MECP2; the disease is Rett syndrome.