Peptidylprolyl isomerase A pseudogene 25 (PPIAP25)

Peptidylprolyl isomerase A pseudogene 25 (abbreviated PPIAP25) is a human pseudogene, meaning it is a DNA sequence similar to a known gene (in this case, PPIA, which encodes cyclophilin A), but it does not produce a functional protein product[2][4][8]. Pseudogenes typically arise from duplication or retrotransposition events and accumulate mutations making them nonfunctional for protein coding[8]. There is no evidence that PPIAP25 itself is expressed at the RNA or protein level, nor is there evidence of direct pathological or therapeutic relevance. Unlike its parent gene PPIA, which is involved in protein folding and implicated in inflammation, cancer, and other biological processes[1][5], PPIAP25 does not encode an active enzyme, receptor, or other functional target and is usually omitted from lists of actionable therapeutic targets. Pseudogenes can sometimes regulate their parent genes at the RNA level (for example, by acting as competing endogenous RNAs/sponges for microRNAs)[6]. Related pseudogenes, such as PPIAP22, have been shown to influence cancer progression by regulating expression of PPIA in hepatocellular carcinoma[3], but there is no such evidence for PPIAP25. PPIAP25 is listed in genomic databases such as GeneCards and BioGPS as a pseudogene only, with no direct function or disease involvement described[2][4]. Pseudogenes do not code for receptors, enzymes, transporters, or similar druggable targets as conventionally defined[8].