Is BLM p.Gln645Ter (c.1933C>T) pathogenic?

BLM p.Gln645Ter (c.1933C>T) is classified Pathogenic in BLM (ClinVar, Multiple submitters, 15 submitters; last evaluated 2026-01-19). Ultra-rare (popmax 0.0132%, nfe); Associated with BLM-related disorder.

What condition is associated with BLM p.Gln645Ter (c.1933C>T)?

BLM p.Gln645Ter (c.1933C>T) is associated with BLM-related disorder, Bloom syndrome, hereditary neoplastic syndrome (ClinVar).

How common is BLM p.Gln645Ter (c.1933C>T) in the general population?

BLM p.Gln645Ter (c.1933C>T) is ultra-rare (popmax 0.0132%, nfe) (gnomAD).

BLM p.Gln645Ter

c.1933C>T · rs373525781 · VCV454091

Pathogenic Multiple submitters

Classification

Pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 15 submitters

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

ultra-rare (popmax 0.0132%, nfe)

Conditions

BLM-related disorder

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Consequence	nonsense (stop-gain)	predicted loss-of-function
NMD	predicted	premature termination codon in exon 8 of 22
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Pangolin	Δ0.25	loss · gain 0.03 · not in the SpliceAI release · independent
Constraint at this position
Conservation	phyloP 5	GERP 2.5, phastCons 1
Overall
CADD	37.0	PHRED · no single calibrated threshold — expert panels disagree

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

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0132% European (non-Finnish) · 156/1,179,870 alleles

Filtering AF 0.0115% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.0108%

Overall 0.00986% 159/1,613,318 alleles · ultra-rare

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.0132%	7,563
Remaining individualsnot grpmax-eligible	0.0048%	20,822

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: BLM
Protein: p.Gln645Ter
Coding: c.1933C>T
MANE Select: NM_000057
dbSNP: rs373525781
Type: single nucleotide variant
Location: chr15:90763016 (GRCh38)
Gene constraint: LOEUF 0.847 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 61.10 · 16 PDB

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

Disease context

BLM-related disorder

Also linked: Bloom syndrome hereditary neoplastic syndrome

Similar variants

BLM p.Gln645Arg Uncertain significance ★★ ⚠ same residue
BLM p.Gln645Leu Uncertain significance ★★ ⚠ same residue
BLM p.Gln645His Uncertain significance ★ ⚠ same residue
BLM p.Gln645= Likely benign ★ same residue
BLM c.1087+1G>A Likely pathogenic ★★ same condition
BLM c.1088-1G>A Likely pathogenic ★★ same condition
BLM c.1220+2T>C Likely pathogenic ★★ same condition
BLM c.1220+2T>G Likely 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/blm-p-gln645ter (accessed [today's date]).

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