ELOVL4 and Menkes disease: Clinical variability exists in the STGD-like MD, even the same gene of different point mutations can cause variance phenotypes [30]; importantly, different genes caused the STGD-like MD, examples include families with ELOVL4 mutation, ABCA4 mutation, and PROM1 mutation [4, 5, 9, 10, 12, 18-20, 22].