chr16-56510871-A-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM1PP3_StrongPP5_Very_Strong

The NM_031885.5(BBS2):c.522T>A(p.Asp174Glu) variant causes a missense change. The variant allele was found at a frequency of 0.0000118 in 1,614,048 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 (★★). Synonymous variant affecting the same amino acid position (i.e. D174D) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

BBS2
NM_031885.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 4.59

Publications

5 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 14 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_031885.5

PP3

MetaRNN computational evidence supports a deleterious effect, 0.946

PP5

Variant 16-56510871-A-T is Pathogenic according to our data. Variant chr16-56510871-A-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 585182.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_031885.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BBS2	NM_031885.5	MANE Select	c.522T>A	p.Asp174Glu	missense	Exon 4 of 17	NP_114091.4
BBS2	NM_001377456.1		c.522T>A	p.Asp174Glu	missense	Exon 4 of 18	NP_001364385.1
BBS2	NR_165293.1		n.684T>A		non_coding_transcript_exon	Exon 4 of 17

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
BBS2	ENST00000245157.11	TSL:1 MANE Select	c.522T>A	p.Asp174Glu	missense	Exon 4 of 17	ENSP00000245157.5
BBS2	ENST00000565781.6	TSL:1	n.536T>A		non_coding_transcript_exon	Exon 4 of 12
BBS2	ENST00000682188.1		c.522T>A	p.Asp174Glu	missense	Exon 4 of 17	ENSP00000507655.1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152180

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:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251484

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

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:

0.0000123

AC:

AN:

1461868

Hom.:

Cov.:

AF XY:

0.00000963

AC XY:

AN XY:

727232

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000671

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000135

AC:

AN:

1112002

Other (OTH)

AF:

0.00

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.506

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

AF:

0.00000657

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74368

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41426

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4838

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Bardet-Biedl syndrome

Pathogenic:3

May 28, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. 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. ClinVar contains an entry for this variant (Variation ID: 585182). This missense change has been observed in individual(s) with Bardet-Biedl syndrome (PMID: 28559085, 30614526). 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 (rs767373822, gnomAD 0.006%). This sequence change replaces aspartic acid, which is acidic and polar, with glutamic acid, which is acidic and polar, at codon 174 of the BBS2 protein (p.Asp174Glu).

Sep 15, 2018

Laboratory of Medical Genetics (UMR_S 1112), INSERM/Strasbourg University

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:provider interpretation

Jun 12, 2025

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

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: BBS2 c.522T>A (p.Asp174Glu) results in a conservative amino acid change in 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 1.2e-05 in 251484 control chromosomes. c.522T>A has been observed in compound heterozygous or homozygous individuals affected with Bardet-Biedl Syndrome (Stone_2017, Mary_2019). 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. The following publications have been ascertained in the context of this evaluation (PMID: 12872256, 30614526, 28559085). ClinVar contains an entry for this variant (Variation ID: 585182). Based on the evidence outlined above, the variant was classified as likely pathogenic.

Bardet-Biedl syndrome 2

Pathogenic:1

Feb 21, 2024

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Bardet-Biedl syndrome 2;C4225281:Retinitis pigmentosa 74

Pathogenic:1

Dec 21, 2023

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.73

BayesDel_addAF

Pathogenic

0.18

BayesDel_noAF

Pathogenic

0.19

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.64

Eigen

Uncertain

0.55

Eigen_PC

Uncertain

0.53

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.89

M_CAP

Uncertain

0.15

MetaRNN

Pathogenic

0.95

MetaSVM

Uncertain

-0.24

PhyloP100

4.6

PrimateAI

Uncertain

0.77

PROVEAN

Uncertain

-3.3

REVEL

Pathogenic

0.65

Sift

Uncertain

0.0070

Sift4G

Uncertain

0.0090

Vest4

0.95

MutPred

0.86

Gain of methylation at K176 (P = 0.0784)

MVP

0.73

MPC

0.85

ClinPred

0.96

GERP RS

4.9

gMVP

0.67

Mutation Taster

=13/87

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over