Is BRCA1 p.Pro1856= (c.5568C>A) pathogenic?

BRCA1 p.Pro1856= (c.5568C>A) is classified Likely benign in BRCA1 (ClinVar, Expert panel, 2 submitters; last evaluated 2017-06-29). Absent from gnomAD v4.1; Associated with breast-ovarian cancer, familial, susceptibility to, 1.

How common is BRCA1 p.Pro1856= (c.5568C>A) in the general population?

BRCA1 p.Pro1856= (c.5568C>A) is absent from gnomAD v4.1 (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.Pro1856=

Q: What condition is associated with BRCA1 p.Pro1856= (c.5568C>A)?

BRCA1 p.Pro1856= (c.5568C>A) is associated with breast-ovarian cancer, familial, susceptibility to, 1, hereditary neoplastic syndrome (ClinVar).

c.5568C>A · rs876659994 · VCV232797

Likely benign Expert panel

Classification

Likely benign

ClinVar

Review

Expert panel ★★★☆

ClinVar · 2 submitters

gnomAD v4.1

Absent

absent from gnomAD v4.1

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.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -1.2	GERP -5.2
Overall
CADD	1.886	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Absent from gnomAD v4.1. Not observed in any sequenced alleles — a rarity signal (ACMG PM2-supporting), not evidence of pathogenicity on its own.

Variant & gene context

Gene: BRCA1
Protein: p.Pro1856=
Coding: c.5568C>A
MANE Select: NM_007294
dbSNP: rs876659994
Type: single nucleotide variant
Location: chr17:43045702 (GRCh38)
Gene constraint: LOEUF 0.885 · pLI <0.01 · ClinGen HI 3/3 (gnomAD)
Structure: AlphaFold pLDDT 41.99 · 33 PDB
Residue 1856: a UniProt-annotated variant site (in fancs); an α-helix

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 neoplastic syndrome

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

Inheritance: Autosomal dominant
Onset: Adult, Elderly

Similar variants

BRCA1 p.Pro1856Ser Likely benign ★★ ⚠ same residue
BRCA1 p.Pro1856Leu Uncertain significance ★ ⚠ same residue
BRCA1 p.Pro1856Thr Conflicting classifications of pathogenicity ★ ⚠ same residue
BRCA1 p.Pro1856Ala Uncertain significance ★ ⚠ same residue
BRCA1 p.Pro1856His Uncertain significance ★ ⚠ same residue
BRCA1 c.134+3A>T Likely pathogenic ★★★ same condition
BRCA1 c.135-1G>T Pathogenic ★★★ same condition
BRCA1 c.212+1G>A 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-pro1856 (accessed [today's date]).

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