Is BRCA1 p.Asn1121fs (c.3362del) pathogenic?

BRCA1 p.Asn1121fs (c.3362del) is classified Pathogenic in BRCA1 (ClinVar, Expert panel, 5 submitters; last evaluated 2016-09-08). Absent from gnomAD; Associated with breast-ovarian cancer, familial, susceptibility to, 1.

What condition is associated with BRCA1 p.Asn1121fs (c.3362del)?

BRCA1 p.Asn1121fs (c.3362del) is associated with breast-ovarian cancer, familial, susceptibility to, 1, hereditary breast ovarian cancer syndrome, hereditary neoplastic syndrome (ClinVar).

How common is BRCA1 p.Asn1121fs (c.3362del) in the general population?

BRCA1 p.Asn1121fs (c.3362del) is absent from gnomAD (gnomAD).

How is Hereditary breast and/or ovarian cancer syndrome inherited?

Typically Autosomal dominant (Orphanet). A genetic counselor can assess individual risk for a family.

BRCA1 p.Asn1121fs

c.3362del · rs80357865 · VCV54858

Pathogenic Expert panel

Classification

Pathogenic

ClinVar

Review

Expert panel ★★★☆

ClinVar · 5 submitters

Consequence

frameshift

predicted LoF

gnomAD v4.1

Not reported

no gnomAD frequency available for this variant

Conditions

breast-ovarian cancer, familial, susceptibility to, 1

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	frameshift	predicted loss-of-function in a haploinsufficient gene (ClinGen)
NMD	predicted	premature termination codon in exon 10 of 23
Splicing
SpliceAI	—	not assessed · substitutions only
Constraint at this position
Conservation	phyloP 1	GERP -3.8

Predicted loss-of-function is descriptive, not an applied PVS1 code.

Population frequency

dbSNP / gnomAD

No gnomAD frequency available for this variant. This is missing data, not an absence: the variant may or may not be present in gnomAD. Rarity (ACMG PM2) and BA1/BS1 cannot be assessed for it.

Variant & gene context

Gene: BRCA1
Protein: p.Asn1121fs
Coding: c.3362del
MANE Select: NM_007294
dbSNP: rs80357865
Type: Deletion
Location: chr17:43092169 (GRCh38)
Gene constraint: LOEUF 0.885 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 41.99 · 33 PDB
Residue 1121: a UniProt-annotated variant site (in fancs)

Full BRCA1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

breast-ovarian cancer, familial, susceptibility to, 1 — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary breast ovarian cancer syndrome hereditary neoplastic syndrome

For Hereditary breast and/or ovarian cancer syndrome (Orphanet):

Inheritance: Autosomal dominant
Onset: Adult, Elderly

Similar variants

BRCA1 p.Asn1121Ter Pathogenic ★★★ same residue
BRCA1 p.Asn1121His Conflicting classifications of pathogenicity ★ ⚠ same residue
BRCA1 p.Asn1121Ser Conflicting classifications of pathogenicity ★ ⚠ same residue
BRCA1 c.302-2del Pathogenic ★★★ same condition
BRCA1 c.4358_4484del Pathogenic ★★★ same condition
BRCA1 c.442-22_442-13del Pathogenic ★★★ same condition
BRCA1 c.4484+1del Pathogenic ★★★ same condition
BRCA1 c.5277+1_5277+6del Pathogenic ★★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/brca1-p-asn1121fs (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown