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Short answer
IMPC stands for the International Mouse Phenotyping Consortium: an international effort, begun in 2011 and involving 21 research institutes in 15 countries, to knock out every protein-coding mouse gene and record what happens. The results are an open, searchable catalogue of mammalian gene function at mousephenotype.org. It is a data resource for researchers, not a clinic, and it needs no login.
Not to be confused with: “IM&PC” and similar names used by internal medicine and pediatrics clinics. They are unrelated to the consortium described here, and nothing on this page is medical advice.
What is the IMPC? (full form and scope)
The full form is International Mouse Phenotyping Consortium. Its stated mission is to create a comprehensive catalogue of mammalian gene function that is freely available to researchers, and its goal is to knock out roughly 20,000 genes, the number that make up the mouse genome. The 2025 Nucleic Acids Research portal paper specifies that every gene is disrupted on the inbred C57BL/6N background and that the work is shared among 21 institutes in 15 countries.
The unit of work is a gene. Each knockout mouse line is put through standardised tests (“phenotyping”), and the measurements are compared with controls to produce phenotype calls: statistical statements that a trait differs significantly in the mutant. If you are new to the underlying technique, see our guide to gene knockout methods, models and validation; for the genetic background, see C57BL/6 substrains (6J vs 6N).
How the data are generated and accessed
The same assays are run in every centre. Standard protocols are published openly through IMPReSS, and the assays fall into 16 categories. Lines are tested as homozygous, hemizygous or heterozygous as appropriate, and phenotype calls are made at embryonic, early adult (under 16 weeks) and mid/late adult stages.
Access routes listed by the consortium and its 2025 paper:
- Web portal: gene pages, allele comparison and a genome browser, with ordering links to the MMRRC and EMMA mouse stock centres.
- Programmatic access: a Solr API, the impc-api Python library, a knowledge graph and a track hub.
- Bulk download: FTP data releases (ftp.ebi.ac.uk/pub/databases/impc/latest/) and batch query.
- Images: about 852 thousand images from 28 procedures; the X-ray images are in the BioImage Archive (S-BIAD2244).
Data release 23.0 in numbers
Figures below are from Data Release 23.0 as reported in the 2025 portal paper (Nucleic Acids Research 54(D1):D1133-D1142, read 2026-11-07). Releases are issued several times a year, so later releases will differ.
| Measure | DR23.0 |
|---|---|
| Data points | More than 100 million |
| Genes with data | 9,277 |
| Independent mouse lines | 9,994 |
| Significant phenotype calls | 113,803 (51,190 embryonic; 57,918 early adult; 4,695 mid/late adult) |
| Candidate disease models | 2,938 candidate models for 1:1 orthologs of Mendelian disease genes |
Gene essentiality categories
For each gene the portal places the knockout in one of five viability categories. This is often the first thing to check, because it tells you whether a homozygous mouse can be studied at all.
| Category | Plain reading |
|---|---|
| Cellular lethal | Loss of the gene is incompatible with cell survival |
| Developmentally lethal | Homozygous embryos do not survive to birth |
| Subviable | Homozygotes are born, but fewer than expected |
| Viable with phenotype | Homozygotes survive and show at least one significant difference |
| Viable with no phenotype | Homozygotes survive and no significant difference was called in the tests run |
The category names come from the 2025 paper; the plain-language readings are our paraphrase of the names. “No phenotype” means none was detected in the assays performed, not that the gene has no function.
A worked path through the portal
- Search the gene symbol and open its gene page.
- Read the essentiality category to see whether homozygous animals are viable.
- Review the phenotype calls by life stage and by assay category.
- Check for a candidate disease model: of 2,581 genes analysed with PhenoDigm, 1,435 candidate models matched at least one human disease phenotype from OMIM, Orphanet or DECIPHER.
- If you want the animals, follow the ordering links to MMRRC or EMMA.
Where it matters for labs
- Choosing or justifying a model: an existing, characterised line may avoid generating a new one. Methods for making and validating knockouts are covered in the gene knockout guide, and CRISPR guide choice in sgRNA design.
- Prior knowledge before a study: viability and baseline phenotypes inform whether a homozygous design is feasible.
- Citation: more than 8,200 papers have been curated as using IMPC reagents or data, so the resource is routinely cited. Cite the data release you used.
Common misunderstandings
- It is not a clinic. IM&PC medical practices share the letters only.
- There is no portal login. The data are open; the consortium states its site content is under CC BY 4.0.
- Candidate models are not diagnoses. They are computed matches between mouse phenotypes and human disease descriptions, intended for research.
- Licence wording differs between sources. The reusabledata.org assessment (read 2026-11-07) graded the resource “all rights reserved” by default because it found no licence in a reasonable place, while the consortium’s current pages and portal paper state CC BY 4.0. Check the licence statement of the release you use.
- Not every gene is done. DR23.0 covers 9,277 genes of roughly 20,000.
FAQ
What is the IMPC?
The International Mouse Phenotyping Consortium, a network of research institutes that knocks out mouse genes and publishes standardised phenotype data openly at mousephenotype.org.
What is the full form of IMPC?
International Mouse Phenotyping Consortium.
What does “physical IMPC” mean?
We found no established meaning for that phrase. It is most likely a mistyped or auto-completed search. The IMPC is a data resource; the physical outputs are mouse lines, which can be requested through the MMRRC and EMMA stock centres.
Is there an IMPC portal login?
No login is described for browsing or downloading the data; access is via the web portal, API, batch query or FTP.
Sources
- IMPC, About the IMPC (read 2026-11-07).
- Nucleic Acids Research 2025;54(D1):D1133-D1142, doi:10.1093/nar/gkaf1148, IMPC portal paper (read 2026-11-07).
- reusabledata.org, International Mouse Phenotyping Consortium (IMPC) (read 2026-11-07).
