MECP2 and Onset: We found associations of FOXG1 mutations with secondary CSF neurotransmitter abnormalities, which have been described in several neurometabolic disorders including MECP2 mutations and early-onset epileptic encephalopathies.19,20 Our observations suggest that further studies are necessary to determine the role of monoamines and related drugs in this condition, in order to optimize treatment regimens for patients with FOXG1 mutations.