6-75923634-C-T

Position:

chr6-75923634-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_001563.4(IMPG1):c.2316G>A(p.Lys772=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000273 in 1,466,552 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000023 ( 0 hom. )

Consequence

IMPG1
NM_001563.4 splice_region, synonymous

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.86

Variant links:

Genes affected

IMPG1 (HGNC:6055): (interphotoreceptor matrix proteoglycan 1) This gene encodes a protein that is a major component of the retinal interphotoreceptor matrix. The encoded protein is a proteoglycan that is thought to play a role in maintaining viability of photoreceptor cells and in adhesion of the neural retina to the retinal pigment epithelium. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Sep 2013]

IMPG1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IMPG1	NM_001563.4 linkuse as main transcript	c.2316G>A	p.Lys772=	splice_region_variant, synonymous_variant	16/17	ENST00000369950.8
IMPG1	NM_001282368.2 linkuse as main transcript	c.2082G>A	p.Lys694=	splice_region_variant, synonymous_variant	15/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IMPG1	ENST00000369950.8 linkuse as main transcript	c.2316G>A	p.Lys772=	splice_region_variant, synonymous_variant	16/17	1	NM_001563.4	P2	Q17R60-1
IMPG1	ENST00000611179.4 linkuse as main transcript	c.2082G>A	p.Lys694=	splice_region_variant, synonymous_variant	15/16	5		A2
IMPG1	ENST00000369952.3 linkuse as main transcript	c.399G>A	p.Lys133=	splice_region_variant, synonymous_variant	3/4	3

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152044

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000421

AC:

AN:

237776

Hom.:

AF XY:

0.00000781

AC XY:

AN XY:

128108

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

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:

0.00000947

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000228

AC:

AN:

1314508

Hom.:

Cov.:

AF XY:

0.00000303

AC XY:

AN XY:

660784

show subpopulations

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:

0.00000306

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152044

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74244

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 02, 2022

The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. 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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant has not been reported in the literature in individuals affected with IMPG1-related conditions. This sequence change affects codon 772 of the IMPG1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the IMPG1 protein. This variant also falls at the last nucleotide of exon 16, which is part of the consensus splice site for this exon. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.28

CADD

Benign

DANN

Benign

0.90

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.96

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.96

Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over