--- title: "FBN1 C1942X (c.5826C>A, rs363806) | Dante Labs" description: "ClinVar classifies FBN1 C1942X as Pathogenic (reviewed by expert panel). Where it sits in the genome, its predicted effect, and the Genome Test reports that look at it." url: "https://dantelabs.com/genes/fbn1/variants/c1942x" --- 1. [Genes](https://dantelabs.com/genes) 2. [FBN1](https://dantelabs.com/genes/fbn1) 3. FBN1 C1942X Variant # FBN1 C1942X NM_000138.5(FBN1):c.5826C>A (p.Cys1942Ter) Also known as - p.Cys1942Ter - p.C1942\* - rs363806 * ClinVar classification Pathogenic * Review status 3 stars out of 4 reviewed by expert panel * Last evaluated 22 February 2024 * Expert panel ClinGen FBN1 Variant Curation Expert Panel, ClinGen Data current to ClinVar release 2026-10-12 · Dante Labs data release 2026.10.16-c6eea6bf Facts last changed 16 October 2026 ## Summary C1942X is a nonsense variant in FBN1: it creates an early stop signal, so the protein the gene encodes is predicted to be cut short. ClinVar classifies it as pathogenic for Marfan Syndrome (reviewed by expert panel). ## ClinVar classifications | Condition | Classification | Review status | Submissions | Last evaluated | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | ----------------------------------------- | ------------ | ---------------- | | [Marfan Syndrome](https://dantelabs.com/conditions/marfan-like-syndromes) [ClinVar VCV000547334 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/547334/) | Pathogenic | 3 stars out of 4 reviewed by expert panel | 1 submission | 22 February 2024 | Classifications as ClinVar records them in release 2026-10-12. ClinVar updates them as evidence is reviewed. ## Where it lies in FBN1 C1942X lies in exon 48 of the 66 in FBN1's MANE Select transcript, NM_000138.5. [FBN1 variants in exon 48 →](https://dantelabs.com/genes/fbn1/variants?exon=48) [FBN1's gene diagram →](https://dantelabs.com/genes/fbn1#gene-structure) ## Molecular details | Gene | [FBN1](https://dantelabs.com/genes/fbn1) | | --------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- | | Transcript | NM_000138.5 MANE Select | | Coding DNA change (HGVS c.) | c.5826C>A | | Protein change (HGVS p.) | p.Cys1942Ter p.C1942\* | | Predicted consequence | Nonsense (stop gained) [stop_gained (opens in a new tab)](https://purl.obolibrary.org/obo/SO_0001587) | | Predicted impact | High | | Position (GRCh38) | chr15:48445467 G>T | | Position (GRCh37) | chr15:48737664 G>T | | dbSNP ID | [rs363806 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/snp/rs363806) | | ClinVar Variation ID | [VCV000547334 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/547334/) | | ClinVar Allele ID | 538046 | | ClinGen Allele Registry ID | [CA269532860 (opens in a new tab)](https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_canonicalid?canonicalid=CA269532860) | | ClinVar name | NM_000138.5(FBN1):c.5826C>A (p.Cys1942Ter) | ## FBN1 C1942X in other databases - [ClinVar VCV000547334 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/clinvar/variation/547334/) - [dbSNP rs363806 (opens in a new tab)](https://www.ncbi.nlm.nih.gov/snp/rs363806) - [ClinGen Allele Registry CA269532860 (opens in a new tab)](https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_canonicalid?canonicalid=CA269532860) - [gnomAD 15-48445467-G-T (opens in a new tab)](https://gnomad.broadinstitute.org/variant/15-48445467-G-T?dataset=gnomad_r4) - [Ensembl rs363806 (opens in a new tab)](https://www.ensembl.org/Homo_sapiens/Variation/Explore?v=rs363806) ## Reports that look at this variant (1) These Genome Test condition reports include C1942X among the variants they look at. | Report | Conditions | Inheritance | | ------------------------------------------------------------------------------- | --------------- | ------------------ | | [Marfan Like Syndromes](https://dantelabs.com/conditions/marfan-like-syndromes) | Marfan Syndrome | Autosomal dominant | ## Other variants in FBN1 - [c.1A>C Pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-1a-c) - [c.989-1G>C Pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-989-1g-c) - [c.4583-5A>G Likely pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-4583-5a-g) - [c.5065+2_5065+3insT Pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-5065plus2to5065plus3inst) - [c.6453C>T Pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-6453c-t) - [c.7204+1G>T Pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-7204plus1g-t) - [c.7330+3_7330+6del Likely pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c-7330plus3to7330plus6del) - [C67R Likely pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c67r) - [C210Y Likely pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c210y) - [C304Y Likely pathogenic 3 stars out of 4](https://dantelabs.com/genes/fbn1/variants/c304y) [All FBN1 variants](https://dantelabs.com/genes/fbn1/variants) ## Limitations This page describes publicly available information about a genetic variant. It is not a diagnosis, and it says nothing about whether you or anyone else carries this variant. Classifications come from ClinVar and change as new evidence is reviewed. A classification here may differ from the one in ClinVar today, or from the one a laboratory reports. Whole genome sequencing with short reads can miss or miscall some variants, particularly in repeated or highly similar stretches of DNA and in large insertions, deletions or rearrangements. If you have questions about a variant in your own results or in your family, talk to a genetic counsellor or your doctor. ## Sources & credits - Classifications from ClinVar (release 2026-10-12), National Center for Biotechnology Information. - Condition terms from the Mondo Disease Ontology (release 2026-10-06), used under CC BY 4.0. - Gene symbols and names from the HUGO Gene Nomenclature Committee (release 2026-10-16). - Allele identifiers from the ClinGen Allele Registry (release 2026-10-16-c4908f54). - Reference SNP identifiers from dbSNP (release b157), National Center for Biotechnology Information. - Gene–disease links from the Gene Curation Coalition, GenCC (release 2026-10-16). - Difficult regions from the Genome in a Bottle Consortium (release v3.6). - Transcripts from MANE (release v1.5), NCBI and EMBL-EBI. - Predicted consequences from mehari (release 0.11.0), with transcript models from cdot. - Built from Dante Labs data release 2026.10.16-c6eea6bf of 16 October 2026. ## Cite this page APA > Dante Labs. (16 October 2026). FBN1 C1942X (c.5826C>A, rs363806) (Version 2026.10.16-c6eea6bf). Retrieved 17 October 2026, from https\://dantelabs.com/genes/fbn1/variants/c1942x Vancouver > Dante Labs. FBN1 C1942X (c.5826C>A, rs363806) \[Internet]. Version 2026.10.16-c6eea6bf. 16 October 2026 \[cited 17 October 2026]. Available from: https\://dantelabs.com/genes/fbn1/variants/c1942x Download citation [RIS](https://dantelabs.com/genes/fbn1/variants/c1942x/cite.ris) [BibTeX](https://dantelabs.com/genes/fbn1/variants/c1942x/cite.bib) [CSL-JSON](https://dantelabs.com/genes/fbn1/variants/c1942x/cite.json) ## Read your whole genome From $449 Free shipping · Results in 6–8 weeks [Explore the Genome Test](https://dantelabs.com/whole-genome-sequencing)