In this study, our aim is to investigate the alteration of cardiac gene expression (ACTC1, MHCα, MHCβ, RYR2, SERCA2, THRα, THRβ, and troponin I) responsive to thyroid hormones in the broiler chickens exposed to low temperature that progressively indicated the signs of PHS and ascites (Davis and Davis, 2002; Dillmann, 2002; Kahaly and Dillmann, 2005). This evidence concerns the gene RYR2 and Pallister-Hall syndrome.