rs113994179

Positions:

• chr11-66523453-C-G
• chr11-66523453-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_024649.5(BBS1):​c.831-3C>G variant causes a splice region, splice polypyrimidine tract, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,880 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BBS1 NM_024649.5 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 4.75

Genes affected

BBS1 (HGNC:966): (Bardet-Biedl syndrome 1) Mutations in this gene have been observed in patients with the major form (type 1) of Bardet-Biedl syndrome. The encoded protein may play a role in eye, limb, cardiac and reproductive system development. [provided by RefSeq, Jul 2008]

ZDHHC24 (HGNC:27387): (zinc finger DHHC-type containing 24) Predicted to enable protein-cysteine S-palmitoyltransferase activity. Predicted to be involved in peptidyl-L-cysteine S-palmitoylation and protein targeting to membrane. Predicted to be integral component of membrane. Predicted to be active in Golgi apparatus and endoplasmic reticulum. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 11-66523453-C-G is Pathogenic according to our data. Variant chr11-66523453-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 21707.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BBS1	NM_024649.5	c.831-3C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000318312.12	NP_078925.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BBS1	ENST00000318312.12	c.831-3C>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_024649.5	ENSP00000317469	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251492 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135922

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 SAS exome AF: 0.0000327

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: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Bardet-Biedl syndrome 1 Pathogenic:1 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics Munich, Klinikum Rechts Der Isar, TU München	Jan 25, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Jan 20, 2020	This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Bardet-Biedl syndrome Pathogenic:1 Uncertain:1

Pathogenic, no assertion criteria provided	curation	GeneReviews	Oct 13, 2009	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Apr 21, 2021	This sequence change falls in intron 9 of the BBS1 gene. It does not directly change the encoded amino acid sequence of the BBS1 protein. It affects a nucleotide within the consensus splice site of the intron. 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. Nucleotide substitutions within 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, but this prediction has not been confirmed by published transcriptional studies. This variant has been observed in individual(s) with clinical features of Bardet-Biedl syndrome (PMID: 12677556). This variant is also known as IVS9-3C>G. ClinVar contains an entry for this variant (Variation ID: 21707). This variant is present in population databases (rs113994179, ExAC 0.006%). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.22
CADD	Pathogenic	28
DANN	Benign	0.94
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.97
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.95		Position offset: 1
DS_AL_spliceai		0.96		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs113994179; hg19: chr11-66290924;