D-Bifunctional Protein Deficiency, also known as bifunctional peroxisomal enzyme deficiency, is related to bifunctional enzyme deficiency and alpha-methylacetoacetic aciduria. An important gene associated with D-Bifunctional Protein Deficiency is HSD17B4 (Hydroxysteroid 17-Beta Dehydrogenase 4), and among its related pathways/superpathways are Metabolism and Fatty acid metabolism. Affiliated tissues include liver and kidney, and related phenotypes are hypotonia and global developmental delay