X-108571432-G-T

Variant names:

• chrX-108571432-G-T
• NM_033380.3:c.404G>T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_033380.3(COL4A5):​c.404G>T​(p.Gly135Val) 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G135D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 22)
• Consequence: COL4A5 NM_033380.3 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 8.38

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 18 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 2 uncertain in NM_033380.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-108571432-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 447209.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.996
• PP5: Variant X-108571432-G-T is Pathogenic according to our data. Variant chrX-108571432-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2609904.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.404G>T	p.Gly135Val	missense_variant	Exon 7 of 53	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.404G>T	p.Gly135Val	missense_variant	Exon 7 of 53	1	NM_033380.3	ENSP00000331902.7
COL4A5	ENST00000361603.7	c.404G>T	p.Gly135Val	missense_variant	Exon 7 of 51	2		ENSP00000354505.2

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 22

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Nov 01, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.404G>T (p.G135V) alteration is located in exon 7 (coding exon 7) of the COL4A5 gene. This alteration results from a G to T substitution at nucleotide position 404, causing the glycine (G) at amino acid position 135 to be replaced by a valine (V). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). Another alteration at the same codon, c.404G>A (p.G135D), has been described in a male with features consistent with COL4A5-related Alport syndrome (Yamawaki, 2022). This amino acid position is highly conserved in available vertebrate species. The p.G135 amino acid is located within the triple-helical domain of the collagen alpha-5 (IV) chain, and this alteration affects one of the highly conserved glycine residues in the Gly-X-Y motif that make up this domain (Ramshaw, 1998). This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -

not provided Pathogenic:1

Dec 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 135 of the COL4A5 protein (p.Gly135Val). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with COL4A5-related conditions. ClinVar contains an entry for this variant (Variation ID: 2609904). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt COL4A5 protein function with a positive predictive value of 95%. 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). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.83
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.94	.;D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	1.0	D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.1	H;H
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-7.9	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	.;D
Vest4		0.94
MutPred		0.99		Gain of sheet (P = 0.0266);Gain of sheet (P = 0.0266);
MVP		1.0
MPC		0.37
ClinPred		1.0	D
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.99
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-107814662; COSMIC: COSV60371502; COSMIC: COSV60371502;