rs770556842

chr12-76346382-CAGTT-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_024685.4(BBS10):c.1599_1602del(p.Thr534IlefsTer21) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,684 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L533L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: BBS10 NM_024685.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 0.356

Genes affected

BBS10 (HGNC:26291): (Bardet-Biedl syndrome 10) This gene is a member of the Bardet-Biedl syndrome (BBS) gene family. Bardet-Biedl syndrome is an autosomal recessive disorder characterized by progressive retinal degeneration, 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 is likely not a ciliary protein but rather has distant sequence homology to type II chaperonins. As a molecular chaperone, this protein may affect the folding or stability of other ciliary or basal body proteins. Inhibition of this protein's expression impairs ciliogenesis in preadipocytes. Mutations in this gene cause Bardet-Biedl syndrome type 10. [provided by RefSeq, Jan 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 33 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-76346382-CAGTT-C is Pathogenic according to our data. Variant chr12-76346382-CAGTT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 188992.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BBS10	NM_024685.4	c.1599_1602del	p.Thr534IlefsTer21	frameshift_variant	2/2	ENST00000650064.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BBS10	ENST00000650064.2	c.1599_1602del	p.Thr534IlefsTer21	frameshift_variant	2/2		NM_024685.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251324 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135830

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 SAS 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: 1461684 Hom.: 0 AF XY: 0.00000275 AC XY: 2 AN XY: 727166

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Bardet-Biedl syndrome 10 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	literature only	Counsyl	Sep 29, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	May 12, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Oct 20, 2022	- -

Bardet-Biedl syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Aug 18, 2019	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the C-terminus of the BBS10 protein. Other variant(s) that disrupt this region (p.Tyr559*) have been determined to be pathogenic (PMID:20472660, 27788217, 28808579). This suggests that variants that disrupt this region of the protein are likely to be causative of disease. This variant has been observed in several individuals affected with Bardet-Biedl syndrome (PMID: 20177705, 24611592, 21642631). ClinVar contains an entry for this variant (Variation ID: 188992). This variant is present in population databases (rs770556842, ExAC 0.001%). This sequence change results in a premature translational stop signal in the BBS10 gene (p.Thr534Ilefs*21). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 190 amino acids of the BBS10 protein. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Oct 17, 2021	Variant summary: BBS10 c.1599_1602delAACT (p.Thr534IlefsX21) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant allele was found at a frequency of 7.9e-06 in 251708 control chromosomes. c.1599_1602delAACT has been reported in the literature in individuals affected with Bardet-Biedl Syndrome (example, Alvarez-Satta_2014, Chen_2011, Muller_2010). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	research	SN ONGC Dept of Genetics and Molecular biology Vision Research Foundation	-	This variant was observed in compound heterozygosity with variant NC_000012.11:g.76741496dup -

BBS10-related condition Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Dec 29, 2023

The BBS10 c.1599_1602delAACT variant is predicted to result in a frameshift and premature protein termination (p.Thr534Ilefs*21). This variant was reported in individuals with Bardet-Biedl syndrome (Muller et al. 2010. PubMed ID: 20177705; Álvarez-Satta et al. 2014. PubMed ID: 24611592; Chen et al. 2011. PubMed ID: 21642631). This variant is reported in 0.0029% of alleles in individuals of Latino descent in gnomAD. Frameshift variants in BBS10 are expected to be pathogenic. This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

LitVar

Other links and lift over

dbSNP: rs770556842; hg19: chr12-76740162;