Dihydrofolate reductase pseudogene 1 (DHFRP1)

Dihydrofolate reductase pseudogene 1 (DHFRP1) is a processed, intronless pseudogene related to the functional *dihydrofolate reductase* (DHFR) gene. DHFRP1 is located on chromosome 18 and, although it shares sequence identity with DHFR, it is not known to be expressed or to encode a functional protein in humans. Unlike the canonical dihydrofolate reductase gene (DHFR) and its functional paralog DHFRL1 (formerly DHFRP4), DHFRP1 lacks a functional promoter and has no evidence of protein expression or enzymatic activity in humans. It is not involved in folate metabolism, disease processes, or drug interaction pathways. Its primary relevance is in evolutionary genomics as an example of gene duplication and retrotransposition events in primate genomes. DHFRP1 is a nonfunctional pseudogene and should not be confused with either the active human DHFR gene or the recently characterized functional paralog DHFRL1. There are no reports of DHFRP1 being expressed, nor does it have an assigned protein product or physiological role. Drugs and inhibitors (such as methotrexate and trimethoprim) that target dihydrofolate reductase do not interact with DHFRP1, but with the functional canonical DHFR enzyme or mitochondrial DHFRL1/2 in humans. Any reference to "DHFRP1" as an active enzyme or drug target is incorrect; it is strictly a genomic artifact. In summary, DHFRP1 is a pseudogene without biological or pharmacological function. It is not a therapeutic target, is not involved in disease, and does not encode a functional protein.

Other names

hDHFR-psi 3DHFRP1dihydrofolate reductase pseudogene 1