X-108695376-G-A

Variant names:

• chrX-108695376-G-A
• rs104886302
• NM_033380.3:c.4931G>A

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_033380.3(COL4A5):​c.4931G>A​(p.Cys1644Tyr) 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. 12/21 in silico tools predict a damaging 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. C1644R) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 23)
• Consequence: COL4A5 NM_033380.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 10.0
• Publications: 4 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 17 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_033380.3
• PM2: Very rare variant in population databases, with high coverage
• 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, 0.993
• PP5: Variant X-108695376-G-A is Pathogenic according to our data. Variant chrX-108695376-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 24780.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_033380.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A5	NM_033380.3	MANE Select	c.4931G>A	p.Cys1644Tyr	missense	Exon 52 of 53	NP_203699.1
	COL4A5	NM_000495.5		c.4913G>A	p.Cys1638Tyr	missense	Exon 50 of 51	NP_000486.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A5	ENST00000328300.11	TSL:1 MANE Select	c.4931G>A	p.Cys1644Tyr	missense	Exon 52 of 53	ENSP00000331902.7
	COL4A5	ENST00000361603.7	TSL:2	c.4913G>A	p.Cys1638Tyr	missense	Exon 50 of 51	ENSP00000354505.2
	COL4A5	ENST00000510690.2	TSL:4	n.1425G>A		non_coding_transcript_exon	Exon 10 of 11

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

Alfa AF: 0.00 Hom.: 0

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

Oct 17, 2024

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is classified as Pathogenic. Evidence in support of pathogenic classification: Variant is absent from gnomAD (both v2 and v3); This variant has moderate previous evidence of pathogenicity in unrelated individuals with Alport syndrome (ClinVar, LOVD, PMIDs: 17277342). Notably, this variant has been detected in patients with Alport syndrome with late onset renal failure without hearing loss or eye abnormalities (PMIDs: 17277342, VCGS cohort); This variant has strong evidence for segregation with disease. It has been reported in a multi-generational family with Alport syndrome (PMID: 17277342); This variant has moderate functional evidence supporting abnormal protein function. Functional analysis showed a significant reduction in heterotrimer formation and secretion (PMID: 20130921); Other missense variants comparable to the one identified in this case have moderate previous evidence for pathogenicity. Changes to serine and tryptophan have been reported as pathogenic or likely pathogenic in individuals with Alport syndrome (ClinVar, LOVD, PMIDs: 26809805, 29270492); Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. Additional information: Variant is predicted to result in a missense amino acid change from cysteine to tyrosine; This variant is heterozygous; This gene is associated with X-linked dominant disease. Males are typically more severely affected than females (PMID: 19965530); Variant is located in the annotated C4 domain (DECIPHER); Dominant negative and loss of function are known mechanisms of disease in this gene and are associated with X-linked Alport syndrome 1 (MIM#301050). Dominant negative is caused mostly by glycine substitutions that affect the conformation of the protein, and loss of function can be caused by either protein truncating or missense variants (PMIDs: 24046192, 12028435); Variants in this gene are known to have variable expressivity. There is intrafamilial variability among affected carrier females, possibly due to variable X-inactivation (PMID: 14514738); Inheritance information for this variant is not currently available in this individual.

May 07, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:1

Dec 09, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects COL4A5 function (PMID: 20130921). 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: 24780). This missense change has been observed in individual(s) with Alport syndrome (PMID: 17277342). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces cysteine, which is neutral and slightly polar, with tyrosine, which is neutral and polar, at codon 1638 of the COL4A5 protein (p.Cys1638Tyr).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.83
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Pathogenic	3.9	H
PhyloP100		10
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-11	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.95		Loss of sheet (P = 0.0817)
MVP		0.99
MPC		1.3
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.99
gMVP		1.0
Mutation Taster		=0/100	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: rs104886302; hg19: chrX-107938606;