rs201196733
Variant summary
Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong
The NM_031885.5(BBS2):c.1864C>T(p.Arg622*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000273 in 1,613,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_031885.5 stop_gained
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: Pathogenic. The variant received 16 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| BBS2 | ENST00000245157.11 | c.1864C>T | p.Arg622* | stop_gained | Exon 15 of 17 | 1 | NM_031885.5 | ENSP00000245157.5 | ||
| ENSG00000288725 | ENST00000684388.1 | n.784C>T | non_coding_transcript_exon_variant | Exon 6 of 14 | ENSP00000507647.1 |
Frequencies
GnomAD3 genomes AF: 0.0000132 AC: 2AN: 152036Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000278 AC: 7AN: 251430 AF XY: 0.0000368 show subpopulations
GnomAD4 exome AF: 0.0000287 AC: 42AN: 1461804Hom.: 0 Cov.: 31 AF XY: 0.0000275 AC XY: 20AN XY: 727198 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000132 AC: 2AN: 152036Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74246 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Bardet-Biedl syndrome 2 Pathogenic:4
This submission and the accompanying classification are no longer maintained by the submitter.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. -
Variant summary: BBS2 c.1864C>T (p.Arg622X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. A truncation downstream of this position has been classified as likely pathogenic by our laboratory, c.2107C>T (p.Arg703X). The variant has been observed with an allele frequency of 2.8e-05 in 246196 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in BBS2 causing Bardet-Biedl Syndrome (2.8e-05 vs. 8.5e-04), allowing no conclusion about variant significance. The variant, c.1864C>T, has been reported in the literature in individuals affected with Bardet-Biedl Syndrome (Bee 2015, Deveault 2011). 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. Multiple ClinVar submissions from clinical diagnostic laboratories (evaluation after 2014) have classified the variant as "likely pathogenic/pathogenic." Based on the evidence outlined above, the variant was classified as pathogenic. -
Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Bardet-Biedl syndrome 2 (MIM#615981) and retinitis pigmentosa 74 (MIM#616562). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0201 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction). (SP) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2: 7 heterozygotes, 0 homozygotes). (SP) 0701 - Other NMD-predicted variants comparable to the one identified in this case have very strong previous evidence for pathogenicity (Decipher; PMID: 31283077). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as likely pathogenic or pathogenic by clinical diagnostic laboratories and has been reported as compound heterozygous in individuals with Bardet-Biedl syndrome 2 (ClinVar; PMIDs: 21344540, 26078953). This variant is also compound heterozygous in one individual with chronic kidney disease without a specific diagnosis and heterozygous in an individual with inherited retinal disease (PMIDs: 33226606, 31429209). (SP) 1203 - This variant has been shown to be de novo in the proband (parental status confirmed) (by trio analysis). (SP) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
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not provided Pathogenic:2
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Bardet-Biedl syndrome 2;C4225281:Retinitis pigmentosa 74 Pathogenic:1
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Bardet-Biedl syndrome Pathogenic:1
This sequence change creates a premature translational stop signal (p.Arg622*) in the BBS2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in BBS2 are known to be pathogenic (PMID: 11285252, 20177705, 24608809, 26518167). This variant is present in population databases (rs201196733, gnomAD 0.006%). This premature translational stop signal has been observed in individuals with Bardet-Biedl syndrome (PMID: 21344540, 26078953). ClinVar contains an entry for this variant (Variation ID: 284737). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at