2-227008066-TGGG-TGG

Variant names:

• chr2-227008066-TG-T
• rs1206142672
• NM_000092.5:c.4760delC

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000092.5(COL4A4):​c.4760delC​(p.Pro1587HisfsTer16) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL4A4 NM_000092.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.778

Genes affected

COL4A4 (HGNC:2206): (collagen type IV alpha 4 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. This particular collagen IV subunit, however, is only found in a subset of basement membranes. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter. Mutations in this gene are associated with type II autosomal recessive Alport syndrome (hereditary glomerulonephropathy) and with familial benign hematuria (thin basement membrane disease). Two transcripts, differing only in their transcription start sites, have been identified for this gene and, as is common for collagen genes, multiple polyadenylation sites are found in the 3' UTR. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 14 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-227008066-TG-T is Pathogenic according to our data. Variant chr2-227008066-TG-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 551963.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A4	NM_000092.5	c.4760delC	p.Pro1587HisfsTer16	frameshift_variant	Exon 47 of 48	ENST00000396625.5	NP_000083.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A4	ENST00000396625.5	c.4760delC	p.Pro1587HisfsTer16	frameshift_variant	Exon 47 of 48	5	NM_000092.5	ENSP00000379866.3
COL4A4	ENST00000682098.1	c.362delC	p.Pro121HisfsTer16	frameshift_variant	Exon 2 of 3			ENSP00000508331.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Sep 16, 2018

Gharavi Laboratory, Columbia University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

May 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Pro1587Hisfs*16) in the COL4A4 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 104 amino acid(s) of the COL4A4 protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with COL4A4-related conditions. ClinVar contains an entry for this variant (Variation ID: 551963). This variant disrupts a region of the COL4A4 protein in which other variant(s) (p.Cys1683Tyr) have been determined to be pathogenic (PMID: 26809805; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. -

Autosomal recessive Alport syndrome;CN376803:Hematuria, benign familial, 1 Pathogenic:1

Mar 02, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive Alport syndrome Pathogenic:1

May 12, 2017

Counsyl

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1206142672; hg19: chr2-227872782;