X-108597479-G-T

Variant names:

• chrX-108597479-G-T
• rs281874674
• NM_033380.3:c.1690G>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_033380.3(COL4A5):​c.1690G>T​(p.Gly564Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: COL4A5 NM_033380.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 9.95

Genes affected

COL4A5 (HGNC:2207): (collagen type IV alpha 5 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. Mutations in this gene are associated with X-linked Alport syndrome, also known as hereditary nephritis. 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. Alternatively spliced transcript variants have been identified for this gene. [provided by RefSeq, Aug 2010]

ACMG classification

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, 0.995
• PP5: Variant X-108597479-G-T is Pathogenic according to our data. Variant chrX-108597479-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 24436.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
COL4A5	NM_033380.3	c.1690G>T	p.Gly564Cys	missense_variant	Exon 24 of 53	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.1690G>T	p.Gly564Cys	missense_variant	Exon 24 of 53	1	NM_033380.3	ENSP00000331902.7
COL4A5	ENST00000483338.1	c.514G>T	p.Gly172Cys	missense_variant	Exon 8 of 20	1		ENSP00000495685.1
COL4A5	ENST00000361603.7	c.1690G>T	p.Gly564Cys	missense_variant	Exon 24 of 51	2		ENSP00000354505.2

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

X-linked Alport syndrome Pathogenic:2

Dec 29, 2022

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: COL4A5 c.1690G>T (p.Gly564Cys) results in a non-conservative amino acid change to a highly conserved residue in the encoded protein sequence. A different missense variant affecting this residue has been classified as likely pathogenic in ClinVar (c.1690G>C, p.Gly564Arg), and other missense variants near this amino acid have been found in association with Alport syndrome (HGMD). Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 183307 control chromosomes. c.1690G>T has been reported in the literature in individuals affected with Alport Syndrome 1, including at least one individual with de novo occurrence (Colville_2009, Yamamyra_2017, Jayasinghe_2021). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. One submitter has provided a clinical-significance assessment for this variant to ClinVar after 2014, and it as pathogenic. The variant changes a highly conserved glycine residue within the triple-helical region. Alterations of glycine residues within the collagen triple-helix are common mechanisms of disease. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Mar 27, 2019

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A heterozygous missense variant, NM_000495.4(COL4A5):c.1690G>T, has been identified in exon 24 of 51 of the COL4A5 gene. The variant is predicted to result in a major amino acid change from glycine to cysteine at position 564 of the protein (NP_000486.1(COL4A5):p.(Gly564Cys)). The glycine residue at this position has very high conservation (100 vertebrates, UCSC), and is located within the collagen triple helix repeat region. In silico predictions for this variant are consistently pathogenic (Polyphen, SIFT, CADD, Mutation Taster). The variant is absent in the gnomAD population database. The variant has been previously described as pathogenic in two patients with alport retinopathy (ClinVar, Colville, D., et al. (2009)). A different variant in the same codon resulting in a change to arginine has also been reported as likely pathogenic in a clinical testing setting (ClinVar). Subsequent analysis of parental samples indicated this variant was due to a de novo event. Based on the information available at the time of curation, this variant has been classified as PATHOGENIC. -

not provided Pathogenic:1

Feb 25, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the triple helix domain of COL4A5. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236). In COL4A5, missense variants at these glycine residues are significantly enriched in individuals with disease (PMID: 23720012, 27627812) compared to the general population (ExAC). 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 COL4A5 protein function. ClinVar contains an entry for this variant (Variation ID: 24436). This missense change has been observed in individual(s) with Alport syndrome (PMID: 19965530, 29270492, 32939031). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 564 of the COL4A5 protein (p.Gly564Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.82
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.73	.;D;T
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.4	H;H;.
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-7.8	D;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;.
Sift4G	Pathogenic	0.0	D;D;.
Polyphen		1.0	.;D;D
Vest4		1.0
MutPred		0.98		Loss of phosphorylation at S565 (P = 0.0793);Loss of phosphorylation at S565 (P = 0.0793);.;
MVP		1.0
MPC		0.32
ClinPred		1.0	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.96
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs281874674; hg19: chrX-107840709;