HSD17B4 and retinal degeneration: However, descriptions of the retinal degeneration in mutant mice are largely confined to studies from Mfp2−/− (Multifunctional Protein 2), Acox1−/− knockout mice, Pex1(G843D) knockin mice and to a lesser extent Gnpat−/− (glycerone-phosphate O-acyltransferase) mice [7–10].