16-56502807-A-C

Variant names:

• chr16-56502807-A-C
• rs886039797
• NM_031885.5:c.806T>G

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PP3_Moderate PP5

The NM_031885.5(BBS2):​c.806T>G​(p.Val269Gly) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 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 predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V269A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BBS2 NM_031885.5 missense, splice_region
• Scores: Splicing: ADA: 0.3501
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.29
• Publications: 1 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.883
• PP5: Variant 16-56502807-A-C is Pathogenic according to our data. Variant chr16-56502807-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 266083.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BBS2	NM_031885.5	c.806T>G	p.Val269Gly	missense_variant, splice_region_variant	Exon 8 of 17	ENST00000245157.11	NP_114091.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BBS2	ENST00000245157.11	c.806T>G	p.Val269Gly	missense_variant, splice_region_variant	Exon 8 of 17	1	NM_031885.5	ENSP00000245157.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251094 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Bardet-Biedl syndrome Pathogenic:1

-

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.82
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;.
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.88	D;D
MetaSVM	Uncertain	-0.0018	T
PhyloP100		9.3
PrimateAI	Uncertain	0.55	T
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.0020	D;D
Vest4		0.88
MutPred		0.60		Gain of disorder (P = 0.0211);Gain of disorder (P = 0.0211);
MVP		0.88
MPC		0.98
ClinPred		0.98	D
GERP RS		5.9
gMVP		0.84
Mutation Taster		=13/87	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.35
dbscSNV1_RF	Benign	0.50
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs886039797; hg19: chr16-56536719;