Genetic Variant BBS2:c.2060-1G>A (chr16-56484868-C-T) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_StrongPM2

The NM_031885.5(BBS2):c.2060-1G>A variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,460,326 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

BBS2
NM_031885.5 splice_acceptor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.27

Publications

0 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: Ambry Genetics, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Myriad Women’s Health
BBS2-related 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:

ENSG00000288725 (HGNC:):

ENSG00000288725 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.22299169 fraction of the gene.

PM2

Very rare variant in population databases, with high coverage;

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	Effect	Exon Rank	Protein	UniProt
BBS2	NM_031885.5	MANE Select	c.2060-1G>A	splice_acceptor intron	N/A	NP_114091.4
BBS2	NM_001377456.1		c.2060-1G>A	splice_acceptor intron	N/A	NP_001364385.1	Q9BXC9
BBS2	NR_165293.1		n.2350-1G>A	splice_acceptor intron	N/A

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
BBS2	ENST00000245157.11	TSL:1 MANE Select	c.2060-1G>A	splice_acceptor intron	N/A	ENSP00000245157.5	Q9BXC9
BBS2	ENST00000565781.6	TSL:1	n.5591-1G>A	splice_acceptor intron	N/A
ENSG00000288725	ENST00000684388.1		n.980-1G>A	splice_acceptor intron	N/A	ENSP00000507647.1	A0A804HJU2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1460326

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726610

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33442

American (AMR)

AF:

0.00

AC:

AN:

44700

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26118

East Asian (EAS)

AF:

0.00

AC:

AN:

39656

South Asian (SAS)

AF:

0.00

AC:

AN:

86222

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1110686

Other (OTH)

AF:

0.00

AC:

AN:

60346

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.542

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.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.39

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.97

FATHMM_MKL

Pathogenic

0.98

PhyloP100

7.3

GERP RS

5.3

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.81

Position offset: -15

DS_AL_spliceai

1.0

Position offset: -1

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over