CYP27A1 and hydrops fetalis: Low vitamin D-contained HF diet significantly aggravated HF-decreased muscle gene expression involved in vitamin D responsive genes including CYP24 and CYP27, fatty acid β-oxidation such as CPT1, PPARα, UCP2, UCP3, VLCAD, and LCAD and mitochondrial biogenesis including PGC1, NRF1, and Tfam without changing mtDNA copy number.