PPARGC1B and cardiomyopathy: ↑ mitochondrial diameter, lipid droplet (LD) and glycogen granule numbers by TEM (10-week-old female),  ↓ PGC1α and PGC1β, ↑ glucose/g tissue, ↓ mito size (by FACS), ↓ mtDNA (10-week-old female), impaired mitochondrial respiration (4- and 8-week-old male) in the hearts and led to cardiomyopathy