Notably, five genes out of six (83.33%) CKD-upregulated programmed cell death (apoptosis)-related genes, including cysteine-rich protein 1 (CRIP1), pleiotrophin (PTN), glutamate Ionotropic receptor NMDA type subunit 2A (GRIN2A), transforming growth factor beta 2 (TGFB2), and frizzled related protein (FRZB), play a role in the positive regulation of apoptotic process and function as proapoptotic genes. The gene discussed is PTN; the disease is chronic kidney disease.