CPT1B and familial dilated cardiomyopathy: However, RT-PCR analysis revealed that Atp2a2 heterozygosity did not impact mRNA levels for Ddit3 (CHOP), Casp12, Hax1, Fabp3, Cpt1b, or Slc2a4 (GLUT4) in DCM/HET hearts when compared with DCM hearts (Table 1).