4-122743307-CCTT-C

Position:

• chr4-122743307-CCTT-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PM4_Supporting

The NM_152618.3(BBS12):​c.1418_1420del​(p.Phe473del) variant causes a inframe deletion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BBS12 NM_152618.3 inframe_deletion
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 1.68

Genes affected

BBS12 (HGNC:26648): (Bardet-Biedl syndrome 12) The protein encoded by this gene is part of a complex that is involved in membrane trafficking. The encoded protein is a molecular chaperone that aids in protein folding upon ATP hydrolysis. This protein also plays a role in adipocyte differentiation. Defects in this gene are a cause of Bardet-Biedl syndrome type 12. Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, May 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_152618.3. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BBS12	NM_152618.3	c.1418_1420del	p.Phe473del	inframe_deletion	2/2	ENST00000314218.8	NP_689831.2
BBS12	NM_001178007.2	c.1418_1420del	p.Phe473del	inframe_deletion	3/3		NP_001171478.1
BBS12	XM_011531680.3	c.1418_1420del	p.Phe473del	inframe_deletion	2/2		XP_011529982.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BBS12	ENST00000314218.8	c.1418_1420del	p.Phe473del	inframe_deletion	2/2	1	NM_152618.3	ENSP00000319062	P1
BBS12	ENST00000542236.5	c.1418_1420del	p.Phe473del	inframe_deletion	3/3	2		ENSP00000438273	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727246

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

BBS12-related disorder Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Nov 16, 2023

The BBS12 c.1418_1420delTCT variant is predicted to result in an in-frame deletion (p.Phe473del). This variant has been reported in homozygous state in an individual with Bardet-Biedl Syndrome (Table S1, Forsythe et al 2016. PubMed ID: 27659767). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Bardet-Biedl syndrome 12 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Counsyl

Feb 15, 2018

- -

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: rs1553941469; hg19: chr4-123664462;