3-101304277-A-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP3_ModeratePP5

The NM_016247.4(IMPG2):c.370T>C(p.Phe124Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000626 in 1,613,764 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). Synonymous variant affecting the same amino acid position (i.e. F124F) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000064 ( 0 hom. )

Consequence

IMPG2
NM_016247.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:1

Conservation

PhyloP100: 8.82

Publications

9 publications found

Variant links:

Genes affected

IMPG2 (HGNC:18362): (interphotoreceptor matrix proteoglycan 2) The protein encoded by this gene binds chondroitin sulfate and hyaluronan and is a proteoglycan. The encoded protein plays a role in the organization of the interphotoreceptor matrix and may promote the growth and maintenance of the light-sensitive photoreceptor outer segment. Defects in this gene are a cause of retinitis pigmentosa type 56 and maculopathy, IMPG2-related.[provided by RefSeq, Mar 2011]

IMPG2 Gene-Disease associations (from GenCC):

vitelliform macular dystrophy 5
Inheritance: AD, Unknown Classification: DEFINITIVE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae)
inherited retinal dystrophy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
retinitis pigmentosa 56
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
adult-onset foveomacular vitelliform dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
retinitis pigmentosa
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

IMPG2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.848

PP5

Variant 3-101304277-A-G is Pathogenic according to our data. Variant chr3-101304277-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 3550.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IMPG2	NM_016247.4 link	c.370T>C	p.Phe124Leu	missense_variant	Exon 3 of 19	ENST00000193391.8	NP_057331.2	Q9BZV3F1T0J3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IMPG2	ENST00000193391.8 link	c.370T>C	p.Phe124Leu	missense_variant	Exon 3 of 19	1	NM_016247.4	ENSP00000193391.6		Q9BZV3

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152136

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:

0.0000943

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000637

AC:

AN:

251240

AF XY:

0.0000589

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000132

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000643

AC:

AN:

1461628

Hom.:

Cov.:

AF XY:

0.0000591

AC XY:

AN XY:

727122

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.0000562

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000783

AC:

AN:

1111782

Other (OTH)

AF:

0.0000497

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

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

AF:

0.0000460

AC:

AN:

152136

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74314

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41436

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.0000943

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000882

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2084

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000100

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.0000824

AC:

EpiCase

AF:

0.000327

EpiControl

AF:

0.000415

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Dec 02, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces phenylalanine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 124 of the IMPG2 protein (p.Phe124Leu). This variant is present in population databases (rs201893545, gnomAD 0.01%). This missense change has been observed in individual(s) with rod-cone dystrophy or autosomal recessive maculopathy (PMID: 20673862; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 3550). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. For these reasons, this variant has been classified as Pathogenic. -

Vitelliform macular dystrophy 5

Pathogenic:1

Dec 01, 2014

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Retinal dystrophy

Pathogenic:1

Jan 01, 2018

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Retinitis pigmentosa

Pathogenic:1

Jun 23, 2019

Sharon lab, Hadassah-Hebrew University Medical Center

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Retinitis pigmentosa 56

Uncertain:1

May 21, 2020

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

A heterozygous missense variant was identified, NM_016247.3(IMPG2):c.370T>C in exon 3 of the IMPG2 gene. This substitution is predicted to create a minor amino acid change from a phenylalanine to a leucine at position 124 of the protein; NP_057331.2(IMPG2):p.(Phe124Leu). The phenylalanine at this position has very high conservation (100 vertebrates, UCSC), and is not situated in a known functional domain (NCBI, PDB). In silico software predictions of the pathogenicity of this variant are conflicting (PolyPhen2, FATHMM, MutationAssessor, PROVEAN). The variant is present in the gnomAD population database at a global population frequency of 0.007% (19 heterozygotes, 0 homozygotes) with a European sub-population frequency of 0.01%. This variant has been previously reported as pathogenic (ClinVar; Bandah-Rozenfeld, D. et al. (2010)). Based on information available at the time of curation, this variant has been classified as a VUS with POTENTIAL CLINICAL RELEVANCE. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.23

BayesDel_noAF

Pathogenic

0.35

CADD

Pathogenic

(source)

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.53

Eigen

Pathogenic

0.88

Eigen_PC

Pathogenic

0.85

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.90

M_CAP

Uncertain

0.11

MetaRNN

Pathogenic

0.85

MetaSVM

Uncertain

0.42

MutationAssessor

Pathogenic

3.2

PhyloP100

8.8

PrimateAI

Uncertain

0.73

PROVEAN

Pathogenic

-4.9

REVEL

Pathogenic

0.91

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.94

MutPred

0.58

Gain of MoRF binding (P = 0.1145);

MVP

0.72

MPC

0.45

ClinPred

0.90

GERP RS

5.8

Varity_R

0.85

gMVP

0.73

Mutation Taster

=17/83

disease causing

(source)

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over