rs766873519

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_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. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R403H) has been classified as Uncertain significance.

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

Publications

5 publications found
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]
BBS2 Gene-Disease associations (from GenCC):
  • Bardet-Biedl syndrome 2
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Myriad Women’s Health
  • ciliopathy
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • retinitis pigmentosa 74
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
  • retinitis pigmentosa
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Bardet-Biedl syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

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
GnomAD2 exomes
AF:
0.0000676
AC:
17
AN:
251492
AF XY:
0.0000809
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 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
African (AFR)
AF:
0.0000299
AC:
1
AN:
33478
American (AMR)
AF:
0.0000447
AC:
2
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.0000580
AC:
5
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.000173
AC:
1
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000522
AC:
58
AN:
1112002
Other (OTH)
AF:
0.0000828
AC:
5
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.453
Heterozygous variant carriers
0
5
11
16
22
27
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
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
African (AFR)
AF:
0.00
AC:
0
AN:
41488
American (AMR)
AF:
0.000196
AC:
3
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5186
South Asian (SAS)
AF:
0.000208
AC:
1
AN:
4810
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10580
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000735
AC:
5
AN:
68004
Other (OTH)
AF:
0.00
AC:
0
AN:
2108
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.436
Heterozygous variant carriers
0
1
2
2
3
4
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
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
-
Breakthrough Genomics, Breakthrough Genomics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:not provided

- -

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) -

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
May 22, 2025
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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. 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), allowing no conclusion about variant significance. c.1207C>T has been reported in the literature in at least one homozygous individual 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). ClinVar contains an entry for this variant (Variation ID: 319857). 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:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

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
PhyloP100
0.59
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
Mutation Taster
=12/88
disease causing

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

Other links and lift over

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