Besides single nucleotide variants, the causative role of GRIA3 in XLID patients has been suggested also for Xq25 copy number variants [18, 26–30] (CNVs) and for a balanced t(X;12)(q24;q15) translocation disrupting the GRIA3 gene [31]. The gene discussed is GRIA3; the disease is cask-related x-linked intellectual disability.