P2RX7 and familial dilated cardiomyopathy: Among this gene cluster, the mRNA expression levels of the P2X purinoceptor 7 (P2RX7) and transmembrane protein 175 (TMEM175) genes were significantly upregulated (≥1.3-fold; P < 0.05), whereas those of neutrophil cytosolic factor 4 (NCF4) gene were significantly downregulated (≥1.3-fold decrease; P < 0.05) in the patients with DCM (Fig 2).