X-108668373-G-T

Position:

• chrX-108668373-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.3659G>T​(p.Gly1220Val) 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. G1220D) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 22)
• Consequence: COL4A5 ENST00000328300.11 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.46

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 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 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-108668373-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 24666.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant X-108668373-G-T is Pathogenic according to our data. Variant chrX-108668373-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 453113.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.3659G>T	p.Gly1220Val	missense_variant	41/53	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.3659G>T	p.Gly1220Val	missense_variant	41/53	1	NM_033380.3	ENSP00000331902
COL4A5	ENST00000361603.7	c.3659G>T	p.Gly1220Val	missense_variant	41/51	2		ENSP00000354505	P1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 22

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Oct 25, 2017

The G1220V variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The G1220V variant is not observed in large population cohorts (Lek et al., 2016). G1220V occurs in the triple helical domain and replaces the Glycine in the canonical Gly-X-Y repeat. Variants in these Glycines result in poor winding of the collagen triple helix and a less functional protein. The G1220V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. Missense variants in the same Glycine residue (G1220D) and in nearby Glycine residues (G1214E, G1217D, G1223V/D) have been reported in the Human Gene Mutation Database in association with COL4A5-related disorders (Stenson et al., 2014), supporting the functional importance of this region of the protein. In summary, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.72	D
BayesDel_noAF	Pathogenic	0.80
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.94	.;D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.89	D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.8	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-7.2	D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.0020	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	.;D
Vest4		0.98
MutPred		0.98		Loss of relative solvent accessibility (P = 0.008);Loss of relative solvent accessibility (P = 0.008);
MVP		0.99
MPC		0.37
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.99
gMVP		1.0

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

Other links and lift over

dbSNP: rs104886251; hg19: chrX-107911603;