X-108668373-G-T

Variant names:

• chrX-108668373-G-T
• rs104886251
• NM_033380.3:c.3659G>T

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_033380.3(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 NM_033380.3 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.46
• Publications: 7 publications found

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]

COL4A5 Gene-Disease associations (from GenCC):

• Alport syndrome

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen, G2P
• X-linked Alport syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Genomics England PanelApp, Myriad Women’s Health, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 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-108668373-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 24666.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 538 curated pathogenic missense variants (we use a threshold of 10). The gene has 138 curated benign missense variants. Gene score misZ: 2.4995 (below the threshold of 3.09). Trascript score misZ: NaN (below the threshold of 3.09). GenCC associations: The gene is linked to X-linked Alport syndrome, Alport syndrome.
• 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 VariationId is 453113.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.3659G>T	p.Gly1220Val	missense_variant	Exon 41 of 53	ENST00000328300.11	NP_203699.1

Ensembl

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

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

Oct 25, 2017

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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
PhyloP100		9.5
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
Mutation Taster		=5/95	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs104886251; hg19: chrX-107911603;