The frequency of the DGS deletion (N = 8), Williams-Beuren syndrome (WBS) deletion (N = 5), and 47,XXY (N = 7) in the ES patients with PCNVs is 5.3% (20/374), which is much lower than the reported frequency of 11.3% (57/506) in patients referred only for CMA [12]. The gene discussed is TBX1; the disease is Williams syndrome.