Is BRCA1 c.441+18C>T pathogenic?

BRCA1 c.441+18C>T is classified Benign/Likely benign in BRCA1 (ClinVar, Multiple submitters, 16 submitters; last evaluated 2026-01-27). Ultra-rare (popmax 0.0341%, mid); Associated with hereditary neoplastic syndrome.

What condition is associated with BRCA1 c.441+18C>T?

BRCA1 c.441+18C>T is associated with hereditary neoplastic syndrome, hereditary breast ovarian cancer syndrome, breast-ovarian cancer, familial, susceptibility to, 1 (ClinVar).

How common is BRCA1 c.441+18C>T in the general population?

BRCA1 c.441+18C>T is ultra-rare (popmax 0.0341%, mid) (gnomAD).

BRCA1 c.441+18C>T

rs371973519 · VCV215873

Benign/Likely benign Multiple submitters

Classification

Benign/Likely benign

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 16 submitters

gnomAD v4.1

Rare

ultra-rare (popmax 0.0341%, mid)

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
Splice region	donor +18	near-intronic (+18 nt from the splice site)
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP -0.17	GERP -2.4, phastCons 0.003
Non-coding constraint	Z 0.28	1 kb window · o/e 0.98 · regional · uncalibrated
Overall
CADD	0.385	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0341% Middle Eastern · 2/5,864 alleles

Filtering AF 0.0093% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00703%

Overall 0.00769% 120/1,561,146 alleles · ultra-rare

Ancestry group	Frequency	1 in
Middle Easterngrpmax	0.0341%	2,932
Admixed American	0.0173%	5,791
Remaining individualsnot grpmax-eligible	0.0132%	7,582
European (non-Finnish)	0.00824%	12,136
African / African-American	0.00414%	24,160
South Asian	0.00228%	43,932
Finnishnot grpmax-eligible	0.00162%	61,754

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: BRCA1
Coding: c.441+18C>T
MANE Select: NM_007294
dbSNP: rs371973519
Type: single nucleotide variant
Location: chr17:43104104 (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.134+3A>T Likely pathogenic ★★★ same condition
BRCA1 c.135-1G>T Pathogenic ★★★ same condition
BRCA1 c.212+1G>A Pathogenic ★★★ same condition
BRCA1 c.212+1G>T Pathogenic ★★★ same condition
BRCA1 c.212+3A>G Pathogenic ★★★ same condition
BRCA1 c.213-12A>G Pathogenic ★★★ same condition
BRCA1 c.213-15A>G Likely pathogenic ★★★ same condition
BRCA1 c.302-1G>C 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-441-plus-18c-t (accessed [today's date]).

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