rs770258677

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_031885.5(BBS2):c.661delC(p.Leu221PhefsTer25) variant causes a frameshift change. The variant allele was found at a frequency of 0.000013 in 1,613,972 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

BBS2
NM_031885.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:10

Conservation

PhyloP100: 5.69

Publications

1 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

BBS2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 16-56506175-AG-A is Pathogenic according to our data. Variant chr16-56506175-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 208564.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
BBS2	NM_031885.5 link	c.661delC	p.Leu221PhefsTer25	frameshift_variant	Exon 6 of 17	ENST00000245157.11	NP_114091.4	Q9BXC9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BBS2	ENST00000245157.11 link	c.661delC	p.Leu221PhefsTer25	frameshift_variant	Exon 6 of 17	1	NM_031885.5	ENSP00000245157.5		Q9BXC9

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152254

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.0000942

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251270

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000185

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000137

AC:

AN:

1461718

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727150

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39676

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.000169

AC:

AN:

53370

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00000989

AC:

AN:

1111926

Other (OTH)

AF:

0.00

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152254

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41468

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.0000942

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68052

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000868

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bardet-Biedl syndrome 2

Pathogenic:4

Jan 20, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Leu221PhefsX25 variant in BBS2 has been reported in 1 homozygous and 2 compound heterozygous individuals with Bardet-Biedl syndrome (BBS; Hjortshøj 2010). This variant has been identified in 0.03% (2/6592) of European (Finnish) chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 221 and leads to a premature termination codon 25 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Complete loss of BBS2 function is an established disease mechanism in BBS. In summary, this variant meets our criteria to be classified as pathogenic for BBS in an autosomal recessive manner. -

Mar 12, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Sep 16, 2020

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Mar 15, 2017

Counsyl

Significance:Likely pathogenic

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. -

Bardet-Biedl syndrome

Pathogenic:2

Jan 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Leu221Phefs*25) 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 (rs770258677, gnomAD 0.02%). This premature translational stop signal has been observed in individuals with Bardet-Biedl syndrome (PMID: 20120035). ClinVar contains an entry for this variant (Variation ID: 208564). For these reasons, this variant has been classified as Pathogenic. -

Jun 06, 2022

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BBS2 c.661delC (p.Leu221PhefsX25) 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. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 2e-05 in 251270 control chromosomes (gnomAD). c.661delC has been reported in the literature in both homozygous and compound heterozygous individuals affected with Bardet-Biedl Syndrome (Hjortshoj_2010). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six ClinVar submitters have assessed the variant since 2014: one classified the variant as likely pathogenic and five classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Inborn genetic diseases

Pathogenic:1

Feb 23, 2021

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.661delC (p.L221Ffs*25) alteration, located in exon 6 (coding exon 6) of the BBS2 gene, consists of a deletion of one nucleotide at position 661, causing a translational frameshift with a predicted alternate stop codon after 25 amino acids. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, the BBS2 c.661delC alteration has an overall frequency of <0.01% (7/282674) total alleles studied. The highest observed frequency was 0.02% (5/25080) of European (Finnish) alleles. This pathogenic alteration has been reported in multiple unrelated individuals with Bardet-Biedl syndrome (BBS) in the homozygous state or in conjunction with a second pathogenic BBS2 allele (Hjortshøj, 2010). Based on the available evidence, this alteration is classified as pathogenic. -

not provided

Pathogenic:1

Oct 23, 2020

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Bardet-Biedl syndrome 2;C4225281:Retinitis pigmentosa 74

Pathogenic:1

Jan 26, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Retinitis pigmentosa

Pathogenic:1

Apr 01, 2018

Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

5.7

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

rs770258677

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over