The FOXG1-related syndrome was initially described as a congenital variant of the RTT (2–4), but phenotypic studies found different features from it, like the presence of hyperkinetic movements in early infancy and characteristic brain imaging abnormalities, as well as the lack of regression and lack of respiratory arrhythmias (5–8, 11). This evidence concerns the gene FOXG1 and cardiac arrhythmia.