Is BRCA1 c.5277+1del pathogenic?

BRCA1 c.5277+1del is classified Pathogenic/Likely pathogenic in BRCA1 (ClinVar, Multiple submitters, 11 submitters; last evaluated 2025-12-02). Absent from gnomAD; Associated with hereditary neoplastic syndrome.

What condition is associated with BRCA1 c.5277+1del?

BRCA1 c.5277+1del is associated with hereditary neoplastic syndrome, hereditary breast ovarian cancer syndrome, breast-ovarian cancer, familial, susceptibility to, 1 (ClinVar).

How common is BRCA1 c.5277+1del in the general population?

BRCA1 c.5277+1del is absent from gnomAD (gnomAD).

BRCA1 c.5277+1del

rs273901754 · VCV91644

Pathogenic/Likely pathogenic Multiple submitters

Classification

Pathogenic/Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 11 submitters

Consequence

canonical splice-site (±1/±2)

predicted LoF

gnomAD v4.1

Not reported

no gnomAD frequency available for this variant

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	canonical splice-site (±1/±2)	predicted loss-of-function in a haploinsufficient gene (ClinGen)
Splicing
Splice region	donor +1	canonical splice dinucleotide (donor +1) · inside the BP7-excluded zone
SpliceAI	—	not assessed · substitutions only
Constraint at this position
Conservation	phyloP 11	GERP 1.6, phastCons 1

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
Coding: c.5277+1del
MANE Select: NM_007294
dbSNP: rs273901754
Type: Deletion
Location: chr17:43057051 (GRCh38)
Gene constraint: LOEUF 0.885 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 41.99 · 33 PDB

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

Disease context

hereditary neoplastic syndrome — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

Also linked: hereditary breast ovarian cancer syndrome breast-ovarian cancer, familial, susceptibility to, 1

Similar variants

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
BRCA1 c.5278-2del Pathogenic ★★★ same condition
BRCA1 c.5333-36_5406+400del Pathogenic ★★★ same condition
BRCA1 c.5470_5477del 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-c-5277-plus-1del (accessed [today's date]).

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