Is BLM p.Ala1327Thr (c.3979G>A) pathogenic?

BLM p.Ala1327Thr (c.3979G>A) is classified Conflicting classifications of pathogenicity in BLM (ClinVar, Conflicting submitters, 2 submitters; last evaluated 2023-12-14). AlphaMissense: likely benign (0.0755); Very rare (popmax 0.00223%, eas); Associated with hereditary neoplastic syndrome.

What condition is associated with BLM p.Ala1327Thr (c.3979G>A)?

BLM p.Ala1327Thr (c.3979G>A) is associated with hereditary neoplastic syndrome, Bloom syndrome (ClinVar).

How common is BLM p.Ala1327Thr (c.3979G>A) in the general population?

BLM p.Ala1327Thr (c.3979G>A) is very rare (popmax 0.00223%, eas) (gnomAD).

What do computational predictors say about BLM p.Ala1327Thr (c.3979G>A)?

AlphaMissense predicts likely benign (score 0.0755) — an in-silico prediction, not a clinical call.

BLM p.Ala1327Thr

c.3979G>A · rs2151199875 · VCV2857568

Conflicting classifications of pathogenicity Conflicting submitters

Classification

Conflicting classifications of pathogenicity

ClinVar

Review

Conflicting submitters ★☆☆☆

ClinVar · 2 submitters

AlphaMissense

likely benign

0.0755 · ACMG-weighted

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Missense predictors

0/3 damaging

AlphaMissense, REVEL, SaProt

Conditions

hereditary neoplastic syndrome

Computational evidence

Protein change
AlphaMissense	0.0755	likely benign
REVEL	0.033	moderately benign-leaning
SaProt	LLR -5.48	tolerated
⇒ AlphaMissense, REVEL and SaProt all call this tolerated.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 1.6	GERP -5.1, phastCons 1
Regional constraint	o/e 0.88	unconstrained · MANE · 6,066 bp · p 0.12 · regional, not allelic
Overall
CADD	5.655	PHRED · no single calibrated threshold — expert panels disagree

AlphaMissense carries the ACMG weight for missense; REVEL and SaProt are independent agreement signals.

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00223% East Asian · 1/44,878 alleles

Overall 6.84e-05% 1/1,461,882 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.Ala1327Thr
Coding: c.3979G>A
MANE Select: NM_000057
dbSNP: rs2151199875
Type: single nucleotide variant
Location: chr15:90811309 (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 1327: the 'disordered' region

Full BLM 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: Bloom syndrome

Similar variants

BLM p.Ala1327Gly Uncertain significance ★★ ⚠ same residue
BLM p.Ala1327Glu Uncertain significance ★ ⚠ same residue
BLM p.Ala1327Ser 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

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-ala1327thr (accessed [today's date]).

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