4-121824928-A-C

Position:

• chr4-121824928-A-C

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_Strong BP6_Moderate BS1 BS2

The NM_176824.3(BBS7):​c.*932T>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00139 in 152,310 control chromosomes in the GnomAD database, including 9 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★).

• Frequency:
  • Genomes: 𝑓 0.0014 (9 hom., cov: 32)
  • Failed GnomAD Quality Control
• Consequence: BBS7 NM_176824.3 3_prime_UTR
• Clinical Significance: Benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.0100

Genes affected

BBS7 (HGNC:18758): (Bardet-Biedl syndrome 7) This gene encodes one of eight proteins that form the BBSome complex containing BBS1, BBS2, BBS4, BBS5, BBS7, BBS8, BBS9 and BBIP10. The BBSome complex is believed to recruit Rab8(GTP) to the primary cilium and promote ciliogenesis. The BBSome complex assembly is mediated by a complex composed of three chaperonin-like BBS proteins (BBS6, BBS10, and BBS12) and CCT/TRiC family chaperonins. Mutations in this gene are implicated in Bardet-Biedl syndrome, a genetic disorder whose symptoms include obesity, retinal degeneration, polydactyly and nephropathy; however, mutations in this gene and the BBS8 gene are thought to play a minor role and mutations in chaperonin-like BBS genes are found to be a major contributor to disease development in a multiethnic Bardet-Biedl syndrome patient population. Two transcript variants encoding distinct isoforms have been identified for this gene.[provided by RefSeq, Oct 2014]

ACMG classification

Verdict is Benign. Variant got -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BP6: Variant 4-121824928-A-C is Benign according to our data. Variant chr4-121824928-A-C is described in ClinVar as [Benign]. Clinvar id is 347470.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.00139 (211/152310) while in subpopulation SAS AF= 0.0417 (201/4824). AF 95% confidence interval is 0.037. There are 9 homozygotes in gnomad4. There are 156 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 9 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BBS7	NM_176824.3	c.*932T>G		3_prime_UTR_variant	19/19	ENST00000264499.9	NP_789794.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BBS7	ENST00000264499	c.*932T>G		3_prime_UTR_variant	19/19	1	NM_176824.3	ENSP00000264499.4
BBS7	ENST00000507814	c.*313T>G		3_prime_UTR_variant	5/5	3		ENSP00000423250.1

Frequencies

GnomAD3 genomes AF: 0.00139 AC: 212 AN: 152192 Hom.: 9 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

Gnomad ASJ AF: 0.000576

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.0418

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AC: 0 AN: 0 Hom.: 0 Cov.: 0 AC XY: 0 AN XY: 0

GnomAD4 genome AF: 0.00139 AC: 211 AN: 152310 Hom.: 9 Cov.: 32 AF XY: 0.00209 AC XY: 156 AN XY: 74476

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.000576

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.0417

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000771 Hom.: 0

Bravo AF: 0.000389

Asia WGS AF: 0.0140 AC: 50 AN: 3476

ClinVar

Significance: Benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bardet-Biedl syndrome 7 Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	3.2
DANN	Benign	0.56

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: rs3217755; hg19: chr4-122746083;