rs281874763

Positions:

• chrX-108578292-G-A
• chrX-108578292-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The ENST00000328300.11(COL4A5):​c.689G>A​(p.Gly230Asp) variant causes a missense, splice region 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. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G230V) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 23)
• Consequence: COL4A5 ENST00000328300.11 missense, splice_region
• Scores: Splicing: ADA: 0.8243
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.06

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 12 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in ENST00000328300.11
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-108578292-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 930192.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.985
• PP5: Variant X-108578292-G-A is Pathogenic according to our data. Variant chrX-108578292-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 1443520.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chrX-108578292-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.689G>A	p.Gly230Asp	missense_variant, splice_region_variant	13/53	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.689G>A	p.Gly230Asp	missense_variant, splice_region_variant	13/53	1	NM_033380.3	ENSP00000331902
COL4A5	ENST00000361603.7	c.689G>A	p.Gly230Asp	missense_variant, splice_region_variant	13/51	2		ENSP00000354505	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 09, 2021

This sequence change replaces glycine with aspartic acid at codon 230 of the COL4A5 protein (p.Gly230Asp). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and aspartic acid. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individuals with Alport syndrome (PMID: 19728970; Invitae). ClinVar contains an entry for this variant (Variation ID: 24316). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). 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). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.72	D
BayesDel_noAF	Pathogenic	0.80
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.74	.;D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-6.4	D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.0030	D;D
Sift4G	Uncertain	0.0030	D;D
Polyphen		1.0	.;D
Vest4		0.97
MutPred		0.86		Gain of relative solvent accessibility (P = 0.09);Gain of relative solvent accessibility (P = 0.09);
MVP		0.99
MPC		0.39
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.94
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.82
dbscSNV1_RF	Benign	0.53
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

Other links and lift over

dbSNP: rs281874763; hg19: chrX-107821522;