2-227094271-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong

The NM_000092.5(COL4A4):c.1223G>A(p.Gly408Glu) variant causes a missense change. The variant allele was found at a frequency of 0.0000109 in 1,461,464 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 Likely pathogenic (★★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

COL4A4
NM_000092.5 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 4.98

Variant links:

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]

COL4A4 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.99

PP5

Variant 2-227094271-C-T is Pathogenic according to our data. Variant chr2-227094271-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 562349.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 link	c.1223G>A	p.Gly408Glu	missense_variant	Exon 20 of 48	ENST00000396625.5	NP_000083.3	P53420

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A4	ENST00000396625.5 link	c.1223G>A	p.Gly408Glu	missense_variant	Exon 20 of 48	5	NM_000092.5	ENSP00000379866.3		P53420

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000241

AC:

AN:

248574

Hom.:

AF XY:

0.0000296

AC XY:

AN XY:

134952

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000499

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000888

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000109

AC:

AN:

1461464

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727018

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.000421

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

Alfa

AF:

0.000102

Hom.:

Bravo

AF:

0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Jun 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 408 of the COL4A4 protein (p.Gly408Glu). This variant is present in population databases (no rsID available, gnomAD 0.05%). This missense change has been observed in individuals with clinical features of Alport syndrome (Invitae). ClinVar contains an entry for this variant (Variation ID: 562349). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt COL4A4 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

Sep 16, 2018

Gharavi Laboratory, Columbia University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

May 02, 2019

Athena Diagnostics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant disrupts a glycine residue in the canonical Gly-X-Y repeats of the triple helix domain, which are required for stability and structure of this protein. Therefore it is expected to severely affect the function of the protein. The best available variant frequency is uninformative because it is below the disease allele frequency. -

Autosomal recessive Alport syndrome

Pathogenic:2

Mar 01, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: COL4A4 c.1223G>A (p.Gly408Glu) results in a non-conservative amino acid change located in the Collagen triple helix repeat (IPR008160) of the encoded protein sequence. This missense variant disrupts a critical glycine residue at position 1 of a Gly-X-Y repeat in the collagenous domain of the collagen IV alpha 4 chain, and variants affecting these glycine residues are significantly enriched in individuals with Alport syndrome (PMID: 33854215). Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.4e-05 in 248574 control chromosomes. c.1223G>A has been reported at a heterozygous state in the literature in at-least one individual affected with Glomerulopathy (Groopman_2019). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 30586318). ClinVar contains an entry for this variant (Variation ID: 562349). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Nov 11, 2019

Division Of Personalized Genomic Medicine, Columbia University Irving Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1223G>A variant in the COL4A4 gene is a missense variant, which results in the substitution of the highly conserved glycine residue at the 408 position to glutamic acid (p.Gly408Glu). This variant localizes to coding exon 20 of the COL4A4 gene (48 exons total; NP_000083.3) and is within the triple helical domain of the protein. To the best of our knowledge, this specific variant has not been described to be associated with disease. However, glycine substitutions within the triple helical domain of this protein are a known mechanism of disease. In silico analysis predicts this change to be deleterious and damaging to the structure and/or function of the protein (probably damaging by PolyPhen2 and damaging by SIFT). This variant has been observed in the Genome Aggregation Database (gnomAD) at a very low frequency (6/248,574), indicating it is not a common benign variant in the populations represented in this database. Of note, allele frequency is higher among individuals of Ashkenazi Jewish descent (5/10,026). Based on the evidence presented, this variant is classified as likely pathogenic. -

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

Pathogenic:1

Mar 01, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Alport syndrome

Pathogenic:1

Sep 20, 2024

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0103 - Loss of function is a known mechanism of disease for this gene and is associated with COL4A4-related nephropathy. Dominant negative is a suspected mechanism of disease for this gene as it is a structural protein (PMIDs: 12028435, 24046192). (I) 0108 - This gene is associated with both recessive and dominant disease. Alport syndrome typically has biallelic inheritance, although rare cases of monoallelic inheritance have been reported (PMID: 28704582). Thin basement membrane nephropathy (TBMN) and focal segmental glomerulosclerosis (FSGS) are associated with autosomal dominant inheritance (OMIM, PMIDs: 16467446, 17942953). (I) 0200 - Variant is predicted to result in a missense amino acid change from glycine to glutamic acid. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (6 heterozygotes, 0 homozygotes). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0601 - Variant is located in the well-established functional triple helical region (UniProt) of the collagen domain (DECIPHER). (SP) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as pathogenic or likely pathogenic by multiple clinical laboratories in ClinVar and has been observed in one individual with Alport syndrome 2 in the literature (PMID: 34993602). (SP) 0906 - Segregation evidence for this variant is inconclusive. This variant has segregated in this individuals brother and nephew, however this is insufficient evidence for pathogenicity. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

COL4A4-related disorder

Pathogenic:1

Aug 02, 2024

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The COL4A4 c.1223G>A variant is predicted to result in the amino acid substitution p.Gly408Glu. This variant was reported in the heterozygous state in an individual with glomerulopathy and family history of kidney disease (Table S7 of Groopman et al. 2019. PubMed ID: 30586318). At PreventionGenetics, we have observed this variant in the heterozygous state in a patient with microhematuria and proteinuria and in another patient with Alport syndrome who also carried a COL4A4 nonsense variant (internal data). The p.Gly408Glu variant affects a glycine (Gly) residue of the conserved triple helical domain (residues 65 – 1459) of the COL4A4 protein (uniprot.org), where substitutions of the glycine (Gly) residue are usually pathogenic (Hudson et al. 1993. PubMed ID: 8253711; https://www.ncbi.nlm.nih.gov/books/NBK1207/). In addition, at other glycine (Gly) residues within this domain, substitutions of a glycine (Gly) with a glutamic acid (Glu) have been widely reported to be pathogenic for autosomal recessive or dominant COL4A4 nephropathy (see for example, autosomal recessive Alport syndrome, p.Gly152Glu at Supplementary Table 1 of Morinière et al. 2014. PubMed ID: 24854265; autosomal dominant focal segmental glomerulosclerosis, p.Gly602Glu in Isaranuwatchai et al. 2023. PubMed ID: 36646731). The c.1223G>A (p.Gly408Glu) variant is reported in 0.050% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.69

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Uncertain

0.13

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.66

Eigen

Pathogenic

0.91

Eigen_PC

Pathogenic

0.80

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.96

M_CAP

Pathogenic

0.64

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

0.95

MutationAssessor

Pathogenic

3.2

PrimateAI

Uncertain

0.74

PROVEAN

Pathogenic

-7.2

REVEL

Pathogenic

0.87

Sift

Uncertain

0.0030

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.73

MutPred

0.95

Loss of glycosylation at P407 (P = 0.1988);

MVP

0.88

MPC

0.71

ClinPred

0.92

GERP RS

5.3

Varity_R

0.66

gMVP

0.91

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over