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
Consequence
NM_031885.5 missense
Scores
Clinical Significance
Conservation
Publications
- Bardet-Biedl syndrome 2Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Myriad Women’s Health
- ciliopathyInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- retinitis pigmentosa 74Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
- retinitis pigmentosaInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Bardet-Biedl syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| BBS2 | ENST00000245157.11 | c.1207C>T | p.Arg403Cys | missense_variant | Exon 10 of 17 | 1 | NM_031885.5 | ENSP00000245157.5 | ||
| ENSG00000288725 | ENST00000684388.1 | n.127C>T | non_coding_transcript_exon_variant | Exon 1 of 14 | ENSP00000507647.1 |
Frequencies
GnomAD3 genomes AF: 0.0000592 AC: 9AN: 152016Hom.: 0 Cov.: 31 show subpopulations
GnomAD2 exomes AF: 0.0000676 AC: 17AN: 251492 AF XY: 0.0000809 show subpopulations
GnomAD4 exome AF: 0.0000493 AC: 72AN: 1461878Hom.: 0 Cov.: 33 AF XY: 0.0000468 AC XY: 34AN XY: 727234 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000592 AC: 9AN: 152132Hom.: 0 Cov.: 31 AF XY: 0.0000672 AC XY: 5AN XY: 74372 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:2
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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
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
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
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
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
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at