rs766873519

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_031885.5(BBS2):​c.1207C>T​(p.Arg403Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000502 in 1,614,010 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 31)
Exomes 𝑓: 0.000049 ( 0 hom. )

Consequence

BBS2
NM_031885.5 missense

Scores

2
16

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:6

Conservation

PhyloP100: 0.588
Variant links:
Genes affected
BBS2 (HGNC:967): (Bardet-Biedl syndrome 2) This gene is a member of the Bardet-Biedl syndrome (BBS) gene family. Bardet-Biedl syndrome is an autosomal recessive disorder characterized by severe pigmentary retinopathy, obesity, polydactyly, renal malformation and cognitive disability. The proteins encoded by BBS gene family members are structurally diverse and the similar phenotypes exhibited by mutations in BBS gene family members is likely due to their shared roles in cilia formation and function. Many BBS proteins localize to the basal bodies, ciliary axonemes, and pericentriolar regions of cells. BBS proteins may also be involved in intracellular trafficking via microtubule-related transport. The protein encoded by this gene forms a multiprotein BBSome complex with seven other BBS proteins.[provided by RefSeq, Oct 2014]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.14493501).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
BBS2NM_031885.5 linkc.1207C>T p.Arg403Cys missense_variant Exon 10 of 17 ENST00000245157.11 NP_114091.4 Q9BXC9

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
BBS2ENST00000245157.11 linkc.1207C>T p.Arg403Cys missense_variant Exon 10 of 17 1 NM_031885.5 ENSP00000245157.5 Q9BXC9
ENSG00000288725ENST00000684388.1 linkn.127C>T non_coding_transcript_exon_variant Exon 1 of 14 ENSP00000507647.1 A0A804HJU2

Frequencies

GnomAD3 genomes
AF:
0.0000592
AC:
9
AN:
152016
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000197
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000208
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.0000676
AC:
17
AN:
251492
Hom.:
0
AF XY:
0.0000809
AC XY:
11
AN XY:
135920
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000289
Gnomad ASJ exome
AF:
0.0000992
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000114
Gnomad OTH exome
AF:
0.000326
GnomAD4 exome
AF:
0.0000493
AC:
72
AN:
1461878
Hom.:
0
Cov.:
33
AF XY:
0.0000468
AC XY:
34
AN XY:
727234
show subpopulations
Gnomad4 AFR exome
AF:
0.0000299
Gnomad4 AMR exome
AF:
0.0000447
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.0000580
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000522
Gnomad4 OTH exome
AF:
0.0000828
GnomAD4 genome
AF:
0.0000592
AC:
9
AN:
152132
Hom.:
0
Cov.:
31
AF XY:
0.0000672
AC XY:
5
AN XY:
74372
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.000196
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.000208
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000735
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.0000818
Hom.:
0
Bravo
AF:
0.0000945
ExAC
AF:
0.0000576
AC:
7
EpiCase
AF:
0.00
EpiControl
AF:
0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:6
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:2
Feb 25, 2024
GeneDx
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 27894351, 22353939) -

-
Breakthrough Genomics, Breakthrough Genomics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: not provided

- -

Bardet-Biedl syndrome Pathogenic:1
Mar 12, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 403 of the BBS2 protein (p.Arg403Cys). This variant is present in population databases (rs766873519, gnomAD 0.02%). This missense change has been observed in individual(s) with Bardet-Biedl syndrome (PMID: 22353939). ClinVar contains an entry for this variant (Variation ID: 319857). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt BBS2 protein function with a negative predictive value of 80%. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not specified Uncertain:1
Dec 19, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: BBS2 c.1207C>T (p.Arg403Cys) results in a non-conservative amino acid change located in the Ciliary BBSome complex subunit 2, C-terminal domain (IPR029333) of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 6.8e-05 in 251492 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in BBS2 causing Bardet-Biedl Syndrome (6.8e-05 vs 0.00098). c.1207C>T has been reported in the literature in at least one homozygous individuals affected with Bardet-Biedl Syndrome (e.g., Abu-Safieh_2012, Shaheen_2016). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 22353939, 27894351). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014, and all submitters classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Bardet-Biedl syndrome 2 Uncertain:1
Jan 27, 2017
Counsyl
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

BBS2-related disorder Uncertain:1
May 17, 2024
PreventionGenetics, part of Exact Sciences
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing

The BBS2 c.1207C>T variant is predicted to result in the amino acid substitution p.Arg403Cys. This variant has been reported in the homozygous state in one individual with Bardet-Biedl syndrome and in the heterozygous state in another individual who also carried other rare variants in Bardet-Biedl syndrome-related genes (Abu-Safieh et al. 2012. PubMed ID: 22353939). The authors did not provide any functional studies to help assess the pathogenicity of the c.1207C>T (p.Arg403Cys) variant. This variant is reported in 0.010% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Bardet-Biedl syndrome 2;C4225281:Retinitis pigmentosa 74 Uncertain:1
Apr 09, 2024
Fulgent Genetics, Fulgent Genetics
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.060
BayesDel_addAF
Benign
-0.034
T
BayesDel_noAF
Uncertain
-0.060
CADD
Benign
12
DANN
Benign
0.52
DEOGEN2
Benign
0.27
T;.
Eigen
Benign
-1.1
Eigen_PC
Benign
-1.1
FATHMM_MKL
Benign
0.27
N
LIST_S2
Benign
0.39
T;.
M_CAP
Benign
0.042
D
MetaRNN
Benign
0.14
T;T
MetaSVM
Benign
-0.73
T
PrimateAI
Benign
0.26
T
PROVEAN
Benign
0.75
N;N
REVEL
Uncertain
0.54
Sift
Benign
0.26
T;T
Sift4G
Benign
0.20
T;T
Vest4
0.69
MVP
0.60
MPC
0.34
ClinPred
0.027
T
GERP RS
-3.8
gMVP
0.39

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.16
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs766873519; hg19: chr16-56535283; COSMIC: COSV55325736; COSMIC: COSV55325736; API