Is BBS2 c.1397+2T>C pathogenic?

BBS2 c.1397+2T>C is classified Likely pathogenic in BBS2 (ClinVar, Multiple submitters, 2 submitters; last evaluated 2023-06-11). Very rare (popmax 0.00223%, eas); Associated with Bardet-Biedl syndrome.

What condition is associated with BBS2 c.1397+2T>C?

BBS2 c.1397+2T>C is associated with Bardet-Biedl syndrome, Bardet-Biedl syndrome 2 (ClinVar).

How common is BBS2 c.1397+2T>C in the general population?

BBS2 c.1397+2T>C is very rare (popmax 0.00223%, eas) (gnomAD).

How is Bardet-Biedl syndrome inherited?

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

BBS2 c.1397+2T>C

rs779506379 · VCV2064812

Likely pathogenic Multiple submitters

Classification

Likely pathogenic

ClinVar

Review

Multiple submitters ★★☆☆

ClinVar · 2 submitters

Consequence

canonical splice-site (±1/±2)

predicted LoF

gnomAD v4.1

Rare

very rare (popmax 0.00223%, eas)

Conditions

Bardet-Biedl syndrome

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation/SpliceAI carries the signal.
Consequence	canonical splice-site (±1/±2)	predicted loss-of-function
Splicing
Splice region	donor +2	canonical splice dinucleotide (donor +2) · inside the BP7-excluded zone
SpliceAI	Δ0.87	donor loss, 2 bp away · masked 0 · deltas
Pangolin	Δ0.65	loss · gain 0.03 · agrees with SpliceAI · independent
Constraint at this position
Conservation	phyloP 11	GERP 1.5, phastCons 1
Overall
CADD	28.4	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 0.00223% East Asian · 1/44,878 alleles

Overall 6.84e-05% 1/1,461,782 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: BBS2
Coding: c.1397+2T>C
MANE Select: NM_031885
dbSNP: rs779506379
Type: single nucleotide variant
Location: chr16:56500852 (GRCh38)
Gene constraint: LOEUF 0.892 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 89.49

Full BBS2 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

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

Also linked: Bardet-Biedl syndrome 2

For Bardet-Biedl syndrome (Orphanet):

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

Similar variants

BBS2 c.118-1G>T Likely pathogenic ★★ same condition
BBS2 c.118-2A>C Likely pathogenic ★★ same condition
BBS2 c.118-2A>G Likely pathogenic ★★ same condition
BBS2 c.1225+2T>C Likely pathogenic ★★ same condition
BBS2 c.1225+2T>G Likely pathogenic ★★ same condition
BBS2 c.1397+1G>A Pathogenic/Likely pathogenic ★★ same condition
BBS2 c.1398-2A>G Likely pathogenic ★★ same condition
BBS2 c.1527+1G>A 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/bbs2-c-1397-plus-2t-c (accessed [today's date]).

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