Genetic Variant IMPG2:p.Cys1077Ser (chr3-101232784-C-G) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PM5PP3_Moderate

The NM_016247.4(IMPG2):c.3230G>C(p.Cys1077Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,698 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1077F) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

IMPG2
NM_016247.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.57

Publications

0 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: Likely_pathogenic. The variant received 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-101232784-C-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 162138.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.936

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IMPG2	NM_016247.4 link	c.3230G>C	p.Cys1077Ser	missense_variant	Exon 15 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.3230G>C	p.Cys1077Ser	missense_variant	Exon 15 of 19	1	NM_016247.4	ENSP00000193391.6		Q9BZV3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461698

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727160

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39678

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53390

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111896

Other (OTH)

AF:

0.00

AC:

AN:

60390

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.35

BayesDel_noAF

Pathogenic

0.27

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.63

Eigen

Pathogenic

0.81

Eigen_PC

Pathogenic

0.76

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.93

M_CAP

Uncertain

0.18

MetaRNN

Pathogenic

0.94

MetaSVM

Uncertain

0.14

MutationAssessor

Pathogenic

3.3

PhyloP100

7.6

PrimateAI

Pathogenic

0.82

PROVEAN

Pathogenic

-8.9

REVEL

Pathogenic

0.78

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.98

MutPred

0.76

Gain of MoRF binding (P = 0.1072);

MVP

0.65

MPC

0.46

ClinPred

1.0

GERP RS

5.0

Varity_R

0.91

gMVP

0.99

Mutation Taster

=5/95

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over