chr16-56514574-A-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PP3_StrongPP5_Very_Strong

The NM_031885.5(BBS2):c.224T>G(p.Val75Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,770 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V75A) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

BBS2
NM_031885.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 9.10

Publications

6 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 12 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.943

PP5

Variant 16-56514574-A-C is Pathogenic according to our data. Variant chr16-56514574-A-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 4569.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.224T>G	p.Val75Gly	missense_variant	Exon 2 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.224T>G	p.Val75Gly	missense_variant	Exon 2 of 17	1	NM_031885.5	ENSP00000245157.5		Q9BXC9

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251460

AF XY:

0.00

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:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461770

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727200

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000899

AC:

AN:

1111896

Other (OTH)

AF:

0.00

AC:

AN:

60396

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

Age Distribution

Exome Het

Variant carriers

<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.:

Alfa

AF:

0.0000141

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bardet-Biedl syndrome 2

Pathogenic:3

Apr 01, 2001

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Oct 05, 2023

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dec 08, 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

Dec 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 75 of the BBS2 protein (p.Val75Gly). This variant is present in population databases (rs121908174, gnomAD 0.0009%). This missense change has been observed in individuals with clinical features of Bardet-Biedl syndrome (PMID: 11285252, 28143435, 31456290). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 4569). 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 expected to disrupt BBS2 protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects BBS2 function (PMID: 20498079). For these reasons, this variant has been classified as Pathogenic. -

Jun 23, 2019

Sharon lab, Hadassah-Hebrew University Medical Center

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Bardet-Biedl syndrome 2;C4225281:Retinitis pigmentosa 74

Pathogenic:1

Jan 05, 2025

First Genomix Gene Laboratory, Genetic Diagnostics Department

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

As part of Carrier Screening testing performed at First Genomix, this variant was identified in a heterozygous state in a patient who is not affected with this condition. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.80

BayesDel_addAF

Pathogenic

0.39

BayesDel_noAF

Pathogenic

0.32

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.84

D;.

Eigen

Pathogenic

0.86

Eigen_PC

Pathogenic

0.83

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.78

T;.

M_CAP

Uncertain

0.097

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Uncertain

0.27

PhyloP100

9.1

PrimateAI

Benign

0.46

PROVEAN

Pathogenic

-5.9

D;D

REVEL

Pathogenic

0.90

Sift

Uncertain

0.0010

D;D

Sift4G

Pathogenic

0.0010

D;D

Vest4

0.85

MutPred

0.83

Loss of sheet (P = 0.0181);Loss of sheet (P = 0.0181);

MVP

0.98

MPC

0.96

ClinPred

0.99

GERP RS

5.5

gMVP

0.91

Mutation Taster

=1/99

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

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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