It was verified that, in the cardiomyocytes of db/db mice, the mRNA expression of PGC-1α was decreased, which inhibited the mRNA expression of its downstream transcription factors mitochondrial transcription factor A (TFAM), mitochondrial transcription factor B2 (TFB2M), and nuclear respiratory factor 1 (NRF1), resulting in the impaired mitochondrial biosynthesis of cardiomyocytes, thereby inducing DCM. The gene discussed is PPARGC1A; the disease is familial dilated cardiomyopathy.