2-169487068-G-C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1_ModeratePP5_Very_Strong

The NM_152384.3(BBS5):​c.143-1G>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000755 in 1,456,460 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 0.0000076 ( 0 hom. )

Consequence

BBS5
NM_152384.3 splice_acceptor, intron

Scores

7
1
6
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 7.27

Publications

1 publications found
Variant links:
Genes affected
BBS5 (HGNC:970): (Bardet-Biedl syndrome 5) This gene encodes a protein that has been directly linked to Bardet-Biedl syndrome. The primary features of this syndrome include retinal dystrophy, obesity, polydactyly, renal abnormalities and learning disabilities. Experimentation in non-human eukaryotes suggests that this gene is expressed in ciliated cells and that it is required for the formation of cilia. Alternate transcriptional splice variants have been observed but have not been fully characterized. [provided by RefSeq, Jul 2008]
BBS5 Gene-Disease associations (from GenCC):
  • Bardet-Biedl syndrome 5
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Ambry Genetics, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae)
  • 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: Pathogenic. The variant received 10 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.064327486 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.7, offset of 4, new splice context is: gtctgtgtgcttttacgtAGact. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
PP5
Variant 2-169487068-G-C is Pathogenic according to our data. Variant chr2-169487068-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 569727.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
BBS5NM_152384.3 linkc.143-1G>C splice_acceptor_variant, intron_variant Intron 2 of 11 ENST00000295240.8 NP_689597.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
BBS5ENST00000295240.8 linkc.143-1G>C splice_acceptor_variant, intron_variant Intron 2 of 11 1 NM_152384.3 ENSP00000295240.3
ENSG00000251569ENST00000513963.1 linkc.143-1G>C splice_acceptor_variant, intron_variant Intron 2 of 15 2 ENSP00000424363.1
BBS5ENST00000392663.6 linkc.143-1G>C splice_acceptor_variant, intron_variant Intron 2 of 10 1 ENSP00000376431.2
BBS5ENST00000443151.1 linkn.143-919G>C intron_variant Intron 2 of 5 5 ENSP00000406182.1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD2 exomes
AF:
0.0000398
AC:
10
AN:
251204
AF XY:
0.0000295
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000289
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000755
AC:
11
AN:
1456460
Hom.:
0
Cov.:
29
AF XY:
0.00000828
AC XY:
6
AN XY:
724924
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33322
American (AMR)
AF:
0.000246
AC:
11
AN:
44716
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26082
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39548
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86138
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53270
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5728
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1107464
Other (OTH)
AF:
0.00
AC:
0
AN:
60192
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.434
Heterozygous variant carriers
0
1
2
2
3
4
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
Cov.:
32
Alfa
AF:
0.000142
Hom.:
0
Bravo
AF:
0.0000378

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Bardet-Biedl syndrome 5 Pathogenic:2
Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

May 19, 2021
DBGen Ocular Genomics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

BBS5-related disorder Pathogenic:1
May 22, 2024
PreventionGenetics, part of Exact Sciences
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

The BBS5 c.143-1G>C variant is predicted to disrupt the AG splice acceptor site and interfere with normal splicing. This variant has been reported in the homozygous state as well in the heterozygous state with a second pathogenic variant in individuals with inherited retinal disease and Bardet-Biedl syndrome (Torrefranca et al. 2020. PubMed ID: 32811249; Table 3 in Villanueva-Mendoza et al. 2021. PubMed ID: 34828430; Supp. Table 4 in Perea-Romero. 2022. PubMed ID: 35835773; Villafuerte-de la Cruz et al. 2024. Pubmed ID: 38347443). This variant is reported in 0.029% of alleles in individuals of Latino descent in gnomAD. Variants that disrupt the consensus splice acceptor site in BBS5 are expected to be pathogenic. This variant is interpreted as pathogenic.

not provided Pathogenic:1
Mar 03, 2022
GeneDx
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Canonical splice site variant expected to result in aberrant splicing, although in the absence of functional evidence the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 31589614, 34828430)

Bardet-Biedl syndrome Pathogenic:1
Sep 13, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 569727). Disruption of this splice site has been observed in individual(s) with clinical features of Bardet-Biedl syndrome (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. This variant is present in population databases (no rsID available, gnomAD 0.03%). This sequence change affects an acceptor splice site in intron 2 of the BBS5 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in BBS5 are known to be pathogenic (PMID: 15137946, 16877420, 26325687, 27708425, 28041643, 29806606).

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.23
D
BayesDel_noAF
Pathogenic
0.39
CADD
Pathogenic
33
DANN
Uncertain
1.0
DEOGEN2
Benign
0.0
.;.;.
Eigen
Pathogenic
1.3
Eigen_PC
Pathogenic
1.1
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Benign
0.0
.;.;.
MetaRNN
Benign
0.0
.;.;.
MutationAssessor
Benign
0.0
.;.;.
PhyloP100
7.3
PROVEAN
Benign
0.0
.;.;.
REVEL
Benign
0.0
Sift
Pathogenic
0.0
.;.;.
Sift4G
Pathogenic
0.0
.;.;.
Vest4
0.0
GERP RS
5.7
Mutation Taster
=0/100
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.94
SpliceAI score (max)
0.62
Details are displayed if max score is > 0.2
DS_AG_spliceai
0.23
Position offset: 5
DS_AL_spliceai
0.62
Position offset: 1

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

Publications

Other links and lift over

dbSNP: rs1054138918; hg19: chr2-170343578; API