chr12-76346437-TG-T

Position:

• chr12-76346437-TG-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_024685.4(BBS10):​c.1547delC​(p.Thr516fs) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. T516T) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BBS10 NM_024685.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: -0.0990

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 Likely_pathogenic. Variant got 8 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 11 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-76346437-TG-T is Pathogenic according to our data. Variant chr12-76346437-TG-T is described in ClinVar as [Pathogenic]. Clinvar id is 217440.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr12-76346437-TG-T is described in Lovd as [Pathogenic]. Variant chr12-76346437-TG-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BBS10	NM_024685.4	c.1547delC	p.Thr516fs	frameshift_variant	2/2	ENST00000650064.2	NP_078961.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BBS10	ENST00000650064.2	c.1547delC	p.Thr516fs	frameshift_variant	2/2		NM_024685.4	ENSP00000497413.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Bardet-Biedl syndrome 10 Pathogenic:1

Pathogenic, no assertion criteria provided

research

Department Of Medical Genetics, Faculty Of Medicine, Ege University

Oct 05, 2015

- -

Bardet-Biedl syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 27, 2022

For these reasons, this variant has been classified as Pathogenic. This variant disrupts a region of the BBS10 protein in which other variant(s) (p.Val707*) have been determined to be pathogenic (PMID: 20472660, 22773737, 25982971, 27486776). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. ClinVar contains an entry for this variant (Variation ID: 217440). This premature translational stop signal has been observed in individual(s) with Bardet-Biedl syndrome (PMID: 26518167). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Thr516Asnfs*8) in the BBS10 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 208 amino acid(s) of the BBS10 protein. -

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: rs869025211; hg19: chr12-76740217;