Since patients with L168F ELOVL4 mutation do not have any reported retinal degeneration (30), we determined the effect of the L168F mutation on VLC-PUFA biosynthesis in HEK293 cells transduced with Myc-tagged Elovl4 variants (WT and L168F) or GFP and UT control cells supplemented with 20:5n3. The gene discussed is ELOVL4; the disease is retinal degeneration.