CR1 complement C3b/C4b receptor 1 (Knops blood group)
Gene ID: 1378, updated on 5-Mar-2024Gene type: protein coding
Also known as: KN; C3BR; C4BR; CD35
- See all available tests in GTR for this gene
- Go to complete Gene record for CR1
- Go to Variation Viewer for CR1 variants
Summary
This gene is a member of the receptors of complement activation (RCA) family and is located in the 'cluster RCA' region of chromosome 1. The genome is polymorphic at this locus with allele-specific splice variants encoding different isoforms, based on the presence/absence of long homologous repeats (LHRs). The gene encodes a monomeric single-pass type I membrane glycoprotein found on erythrocytes, leukocytes, glomerular podocytes, and splenic follicular dendritic cells. The Knops blood group system is a system of antigens located on this protein. The protein mediates cellular binding to particles and immune complexes that have activated complement. Decreases in expression of this protein and/or mutations in this gene have been associated with gallbladder carcinomas, mesangiocapillary glomerulonephritis, systemic lupus erythematosus, sarcoidosis and Alzheimer's disease. Mutations in this gene have also been associated with a reduction in Plasmodium falciparum rosetting, conferring protection against severe malaria. [provided by RefSeq, May 2020]
Associated conditions
See all available tests in GTR for this gene
| Description | Tests |
|---|---|
| A genome-wide association scan on the levels of markers of inflammation in Sardinians reveals associations that underpin its complex regulation. GeneReviews: Not available | |
| Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease. GeneReviews: Not available | |
| Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer's disease. GeneReviews: Not available | |
| Complement receptor 1 gene variants are associated with erythrocyte sedimentation rate. GeneReviews: Not available | |
| Genome-wide association study identifies variants at CLU and CR1 associated with Alzheimer's disease. GeneReviews: Not available | |
| KNOPS BLOOD GROUP SYSTEM | See labs |
| Malaria, susceptibility to | See labs |
| Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease. GeneReviews: Not available |
Genomic context
- Location:
- 1q32.2
- Sequence:
- Chromosome: 1; NC_000001.11 (207496157..207641765)
- Total number of exons:
- 47
Variation
| Resource | Links for this gene |
|---|---|
| ClinVar | Variants reported to ClinVar |
| dbVar | Studies and variants |
| SNP | Variation Viewer for CR1 variants |
| Genome viewer | Explore NCBI-annotated and select non-NCBI annotated genome assemblies |
- Blood Group Antigen Gene Mutation Database (BGMUT)
- ClinVarRelated medical variations
- CR1 database
- dbVarLink from Gene to dbVar
- MedGenRelated information in MedGen
- OMIMLink to related OMIM entry
- PubMed (OMIM)Gene links to PubMed derived from omim_pubmed_cited links
- RefSeq RNAsLink to Nucleotide RefSeq RNAs
- RefSeqGeneLink to Nucleotide RefSeqGenes
- Variation ViewerRelated Variants
IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.