The transgene construct has the human cytomegalovirus immediate early promoter enhancer with chicken beta-actin/rabbit beta-globin hybrid promoter (CAG; from the pCAGGS vector) driving expression of a 1.8 kb fragment encoding the human CYP27A1 (cytochrome P450, family 27, subfamily A, polypeptide 1) cDNA sequence. This transgene was microinjected into the pronuclei of fertilized mouse eggs taken from superovulated CBA females. The highest transgenic overexpressor founder mouse (23) was bred to wildtype C57BL/6J (Harlan) mice to establish line 23.