In summary, spectral EEG analysis of ArhGAP15−/− mice shows an increase in the relative power of medium and high frequencies (α, β and γ ranges), a significant increase in the θ low activity (4–6 Hz) and a mild shift of MDF towards lower frequency (α and θ ranges), similar to the mild slowing of background activity seen in most Mowat-Wilson syndrome patients21,22. This evidence concerns the gene ARHGAP15 and Mowat-Wilson syndrome.