chr6-75950867-G-T

Variant names:

• chr6-75950867-G-T
• rs367576664
• NM_001563.4:c.1519C>A

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

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
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.14
• Publications: 0 publications found

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

ACMG classification

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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001563.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IMPG1	NM_001563.4	MANE Select	c.1519C>A	p.Arg507Arg	synonymous	Exon 13 of 17	NP_001554.2
	IMPG1	NM_001282368.2		c.1285C>A	p.Arg429Arg	synonymous	Exon 12 of 16	NP_001269297.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IMPG1	ENST00000369950.8	TSL:1 MANE Select	c.1519C>A	p.Arg507Arg	synonymous	Exon 13 of 17	ENSP00000358966.3
	IMPG1	ENST00000611179.4	TSL:5	c.1285C>A	p.Arg429Arg	synonymous	Exon 12 of 16	ENSP00000481913.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461560 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727078

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

African (AFR) AF: 0.0000299 AC: 1 AN: 33464

American (AMR) AF: 0.00 AC: 0 AN: 44652

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53360

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111878

Other (OTH) AF: 0.00 AC: 0 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.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.56
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

Other links and lift over

dbSNP: rs367576664; hg19: chr6-76660584;