Is BLM p.Gln1262Ter (c.3784C>T) pathogenic?

BLM p.Gln1262Ter (c.3784C>T) is classified Pathogenic in BLM (ClinVar, Single submitter, 1 submitter; last evaluated 2023-05-30). Very rare (popmax 8.47e-05%, nfe); Associated with Bloom syndrome.

What condition is associated with BLM p.Gln1262Ter (c.3784C>T)?

BLM p.Gln1262Ter (c.3784C>T) is associated with Bloom syndrome (ClinVar).

How common is BLM p.Gln1262Ter (c.3784C>T) in the general population?

BLM p.Gln1262Ter (c.3784C>T) is very rare (popmax 8.47e-05%, nfe) (gnomAD).

How is Bloom syndrome inherited?

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

BLM p.Gln1262Ter

c.3784C>T · rs2151198294 · VCV3011339

Pathogenic Single submitter

Classification

Pathogenic

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

Consequence

nonsense (stop-gain)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 8.47e-05%, nfe)

Conditions

Bloom syndrome

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 20 of 22
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 5.9	GERP 2.6, phastCons 1
Overall
CADD	45.0	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 8.47e-05% European (non-Finnish) · 1/1,179,996 alleles

Overall 6.84e-05% 1/1,461,856 alleles · very rare

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.Gln1262Ter
Coding: c.3784C>T
MANE Select: NM_000057
dbSNP: rs2151198294
Type: single nucleotide variant
Location: chr15:90809169 (GRCh38)
Gene constraint: LOEUF 0.847 · pLI <0.01 · ClinGen HI gene assoc. with recessive phenotype (gnomAD)
Structure: AlphaFold pLDDT 61.10 · 16 PDB
Residue 1262: the hrdc domain

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

Disease context

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

For Bloom syndrome (Orphanet):

Inheritance: Autosomal recessive
Onset: Antenatal, Neonatal
Prevalence: 1-9 / 100 000 (Specific population)

Similar variants

BLM p.Gln1262= Conflicting classifications of pathogenicity ★ same residue
BLM p.Gln1262Arg Uncertain significance ★ ⚠ 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
BLM c.1882+2T>C Likely pathogenic ★★ same condition
BLM c.2074+1G>T 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-gln1262ter (accessed [today's date]).

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