Genetic Variant IMPG1:p.Arg507Arg (chr6-75950867-G-T) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_001563.4(IMPG1):c.1519C>A(p.Arg507Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,560 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

IMPG1
NM_001563.4 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -1.14

Publications

0 publications found

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 Gene-Disease associations (from GenCC):

inherited retinal dystrophy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
vitelliform macular dystrophy 4
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Laboratory for Molecular Medicine, ClinGen, G2P, Labcorp Genetics (formerly Invitae)
retinitis pigmentosa
Inheritance: AR, AD Classification: MODERATE Submitted by: Franklin by Genoox
adult-onset foveomacular vitelliform dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

IMPG1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.89).

BP7

Synonymous conserved (PhyloP=-1.14 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IMPG1	NM_001563.4 link	c.1519C>A	p.Arg507Arg	synonymous_variant	Exon 13 of 17	ENST00000369950.8	NP_001554.2
IMPG1	NM_001282368.2 link	c.1285C>A	p.Arg429Arg	synonymous_variant	Exon 12 of 16		NP_001269297.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IMPG1	ENST00000369950.8 link	c.1519C>A	p.Arg507Arg	synonymous_variant	Exon 13 of 17	1	NM_001563.4	ENSP00000358966.3
IMPG1	ENST00000611179.4 link	c.1285C>A	p.Arg429Arg	synonymous_variant	Exon 12 of 16	5		ENSP00000481913.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461560

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727078

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000299

AC:

AN:

33464

American (AMR)

AF:

0.00

AC:

AN:

44652

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39690

South Asian (SAS)

AF:

0.00

AC:

AN:

86244

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53360

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111878

Other (OTH)

AF:

0.00

AC:

AN:

60384

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.89

CADD

Benign

0.56

(source)

DANN

Benign

0.36

PhyloP100

-1.1

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over