chr4-121854739-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 3P and 4B. PM2PP2BP4_Strong

The NM_176824.3(BBS7):c.683G>A(p.Arg228His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000397 in 1,612,050 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R228C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000038 ( 0 hom. )

Consequence

BBS7
NM_176824.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 1.56

Publications

6 publications found

Variant links:

Genes affected

BBS7 (HGNC:18758): (Bardet-Biedl syndrome 7) This gene encodes one of eight proteins that form the BBSome complex containing BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBIP10. The BBSome complex is believed to recruit Rab8(GTP) to the primary cilium and promote ciliogenesis. The BBSome complex assembly is mediated by a complex composed of three chaperonin-like BBS proteins (BBS6, BBS10, and BBS12) and CCT/TRiC family chaperonins. Mutations in this gene are implicated in Bardet-Biedl syndrome, a genetic disorder whose symptoms include obesity, retinal degeneration, polydactyly and nephropathy; however, mutations in this gene and the BBS8 gene are thought to play a minor role and mutations in chaperonin-like BBS genes are found to be a major contributor to disease development in a multiethnic Bardet-Biedl syndrome patient population. Two transcript variants encoding distinct isoforms have been identified for this gene.[provided by RefSeq, Oct 2014]

BBS7 Gene-Disease associations (from GenCC):

Bardet-Biedl syndrome 7
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
ciliopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
Bardet-Biedl syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

BBS7 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 1.2326 (below the threshold of 3.09). Trascript score misZ: 1.7868 (below the threshold of 3.09). GenCC associations: The gene is linked to ciliopathy, Bardet-Biedl syndrome 7, Bardet-Biedl syndrome.

BP4

Computational evidence support a benign effect (MetaRNN=0.06759167).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BBS7	NM_176824.3 link	c.683G>A	p.Arg228His	missense_variant	Exon 7 of 19	ENST00000264499.9	NP_789794.1	Q8IWZ6-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BBS7	ENST00000264499.9 link	c.683G>A	p.Arg228His	missense_variant	Exon 7 of 19	1	NM_176824.3	ENSP00000264499.4		Q8IWZ6-1
BBS7	ENST00000506636.1 link	c.683G>A	p.Arg228His	missense_variant	Exon 7 of 18	1		ENSP00000423626.1		Q8IWZ6-2

Frequencies

GnomAD3 genomes

AF:

0.0000592

AC:

AN:

152052

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251212

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000377

AC:

AN:

1459998

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

726338

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33446

American (AMR)

AF:

0.0000224

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26080

East Asian (EAS)

AF:

0.00

AC:

AN:

39540

South Asian (SAS)

AF:

0.00

AC:

AN:

86048

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53288

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000468

AC:

AN:

1110856

Other (OTH)

AF:

0.0000332

AC:

AN:

60276

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.455

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:

0.0000592

AC:

AN:

152052

Hom.:

Cov.:

AF XY:

0.0000808

AC XY:

AN XY:

74272

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41408

American (AMR)

AF:

0.00

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10566

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

68006

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

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:

0.000214

Hom.:

Bravo

AF:

0.0000378

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 08, 2017

Genetic Services Laboratory, University of Chicago

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

BBS7-related disorder

Uncertain:1

Dec 06, 2023

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The BBS7 c.683G>A variant is predicted to result in the amino acid substitution p.Arg228His. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0062% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Bardet-Biedl syndrome 7

Uncertain:1

Jun 03, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Bardet-Biedl syndrome

Uncertain:1

Apr 13, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 228 of the BBS7 protein (p.Arg228His). This variant is present in population databases (rs369866009, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with BBS7-related conditions. ClinVar contains an entry for this variant (Variation ID: 531821). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The histidine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.060

BayesDel_addAF

Benign

-0.26

BayesDel_noAF

Benign

-0.43

CADD

Benign

(source)

DANN

Benign

0.19

DEOGEN2

Benign

0.098

T;.

Eigen

Benign

-1.1

Eigen_PC

Benign

-0.94

FATHMM_MKL

Benign

0.040

LIST_S2

Benign

0.11

T;T

M_CAP

Benign

0.057

MetaRNN

Benign

0.068

T;T

MetaSVM

Benign

-0.75

MutationAssessor

Benign

-1.6

N;N

PhyloP100

1.6

PrimateAI

Benign

0.39

PROVEAN

Benign

0.78

N;N

REVEL

Benign

0.15

Sift

Benign

1.0

T;T

Sift4G

Benign

0.62

T;T

Polyphen

0.0

B;.

Vest4

0.15

MVP

0.64

MPC

0.21

ClinPred

0.024

GERP RS

2.9

Varity_R

0.019

gMVP

0.15

Mutation Taster

=99/1

polymorphism

(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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over