Enables hydroxymethylglutaryl-CoA synthase activity. Involved in several processes, including animal organ development; cellular response to lipid; and response to peptide hormone. Located in mitochondrial matrix. Biomarker of extrahepatic cholestasis. Orthologous to human HMGCS2 (3-hydroxy-3-methylglutaryl-CoA synthase 2). [provided by Alliance of Genome Resources, Apr 2022]