4-122741894-T-C

Position:

• chr4-122741894-T-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_152618.3(BBS12):​c.2T>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,610 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: BBS12 NM_152618.3 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 0.0380

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 Pathogenic. Variant got 11 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-122741894-T-C is Pathogenic according to our data. Variant chr4-122741894-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 556158.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BBS12	NM_152618.3	c.2T>C	p.Met1?	start_lost	2/2	ENST00000314218.8	NP_689831.2
BBS12	NM_001178007.2	c.2T>C	p.Met1?	start_lost	3/3		NP_001171478.1
BBS12	XM_011531680.3	c.2T>C	p.Met1?	start_lost	2/2		XP_011529982.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BBS12	ENST00000314218.8	c.2T>C	p.Met1?	start_lost	2/2	1	NM_152618.3	ENSP00000319062.3
BBS12	ENST00000542236.5	c.2T>C	p.Met1?	start_lost	3/3	2		ENSP00000438273.1
BBS12	ENST00000433287.1	c.2T>C	p.Met1?	start_lost	3/3	2		ENSP00000398912.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461610 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727128

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: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Bardet-Biedl syndrome 12 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Jan 22, 2018

- -

Bardet-Biedl syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 01, 2022

This sequence change affects the initiator methionine of the BBS12 mRNA. The next in-frame methionine is located at codon 3. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BBS12-related conditions. ClinVar contains an entry for this variant (Variation ID: 556158). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Benign	-0.43
CADD	Benign	16
DANN	Uncertain	0.98
DEOGEN2	Benign	0.026	T;T;.
Eigen	Benign	-0.91
Eigen_PC	Benign	-0.99
FATHMM_MKL	Benign	0.075	N
LIST_S2	Uncertain	0.90	D;.;D
M_CAP	Benign	0.038	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Benign	-0.89	T
PROVEAN	Benign	-0.54	N;N;N
REVEL	Benign	0.16
Sift	Pathogenic	0.0	D;D;D
Sift4G	Uncertain	0.0080	D;D;D
Polyphen		0.0	B;B;.
Vest4		0.10
MutPred		0.98		Gain of catalytic residue at M1 (P = 0.0139);Gain of catalytic residue at M1 (P = 0.0139);Gain of catalytic residue at M1 (P = 0.0139);
MVP		0.61
ClinPred		0.42	T
GERP RS		-0.98
Varity_R		0.76
gMVP		0.12

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: rs1553941150; hg19: chr4-123663049;