Is BLM p.Cys396= (c.1188T>C) pathogenic?

BLM p.Cys396= (c.1188T>C) is classified Likely benign in BLM (ClinVar, Single submitter, 1 submitter; last evaluated 2022-06-23). Very rare (popmax 0.0011%, sas); Associated with Bloom syndrome.

What condition is associated with BLM p.Cys396= (c.1188T>C)?

BLM p.Cys396= (c.1188T>C) is associated with Bloom syndrome (ClinVar).

How common is BLM p.Cys396= (c.1188T>C) in the general population?

BLM p.Cys396= (c.1188T>C) is very rare (popmax 0.0011%, sas) (gnomAD).

How is Bloom syndrome inherited?

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

BLM p.Cys396=

c.1188T>C · rs756454608 · VCV758457

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.0011%, sas)

Conditions

Bloom syndrome

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 0.04	GERP 0.43, phastCons 0.97
Overall
CADD	8.543	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0011% South Asian · 1/91,088 alleles

Overall 6.2e-05% 1/1,614,154 alleles · very rare exomes 1/1,461,832 · genomes 0/152,322 · joint denominator

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.Cys396=
Coding: c.1188T>C
MANE Select: NM_000057
dbSNP: rs756454608
Type: single nucleotide variant
Location: chr15:90760247 (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 396: the 'necessary for interaction with spidr' region; the 'necessary for dimerization and homooligomerization' region

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 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
BLM c.2075-1G>A Likely pathogenic ★★ same condition
BLM c.2193+1G>A Pathogenic/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-cys396 (accessed [today's date]).

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