7-33152855-A-G

Variant names:

• chr7-33152855-A-G
• rs370916293
• NM_198428.3:c.263+4A>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_198428.3(BBS9):​c.263+4A>G variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,600 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BBS9 NM_198428.3 splice_region, intron
• Scores: Splicing: ADA: 0.9991
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 8.87
• Publications: 0 publications found

Genes affected

BBS9 (HGNC:30000): (Bardet-Biedl syndrome 9) This gene is downregulated by parathyroid hormone in osteoblastic cells, and therefore is thought to be involved in parathyroid hormone action in bones. The exact function of this gene has not yet been determined. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jan 2017]

BBS9 Gene-Disease associations (from GenCC):

• Bardet-Biedl syndrome 9

  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

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BBS9	NM_198428.3	c.263+4A>G		splice_region_variant, intron_variant	Intron 3 of 22	ENST00000242067.11	NP_940820.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BBS9	ENST00000242067.11	c.263+4A>G		splice_region_variant, intron_variant	Intron 3 of 22	1	NM_198428.3	ENSP00000242067.6

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251294 AF XY: 0.00

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461600 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727098

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39650

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.0000375 AC: 2 AN: 53370

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111862

Other (OTH) AF: 0.0000166 AC: 1 AN: 60382

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bardet-Biedl syndrome Pathogenic:1 Uncertain:1

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

- -

Nov 01, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been observed in individuals with clinical features of Bardet-Biedl syndrome (PMID: 30614526; Invitae). This variant is present in population databases (rs370916293, gnomAD 0.0009%). ClinVar contains an entry for this variant (Variation ID: 585195). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. This sequence change falls in intron 3 of the BBS9 gene. It does not directly change the encoded amino acid sequence of the BBS9 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.19
CADD	Pathogenic	26
DANN	Benign	0.97
PhyloP100		8.9
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.79		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.48		Position offset: 0
DS_DL_spliceai		0.79		Position offset: -4

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

Other links and lift over

dbSNP: rs370916293; hg19: chr7-33192467;