The perfectly coordinated interaction between ELOVL1 (≥C20-acyl-CoA), ELOVL3 (especially to C18-acyl-CoA, but predominantly to C22-acyl-CoA), ELOVL6 (high affinity to C16-acyl-CoA and C2 chain extension of saturated fatty acids (from C16-acyl-CoA to C18-acyl-CoA)), and ELOVL4 (≥C26-acyl-CoA) are of particular interest in AD, as they enable the formation of a robust skin barrier [46,47,48]. This evidence concerns the gene ELOVL3 and Alzheimer disease.