rs1553644402

Positions:

• chr2-227060216-C-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000092.5(COL4A4):​c.2084G>A​(p.Gly695Asp) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,024 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL4A4 NM_000092.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.58

Genes affected

COL4A4 (HGNC:2206): (collagen type IV alpha 4 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. This particular collagen IV subunit, however, is only found in a subset of basement membranes. 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. Mutations in this gene are associated with type II autosomal recessive Alport syndrome (hereditary glomerulonephropathy) and with familial benign hematuria (thin basement membrane disease). Two transcripts, differing only in their transcription start sites, have been identified for this gene and, as is common for collagen genes, multiple polyadenylation sites are found in the 3' UTR. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 2-227060216-C-T is Pathogenic according to our data. Variant chr2-227060216-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 557759.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-227060216-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A4	NM_000092.5	c.2084G>A	p.Gly695Asp	missense_variant	27/48	ENST00000396625.5	NP_000083.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A4	ENST00000396625.5	c.2084G>A	p.Gly695Asp	missense_variant	27/48	5	NM_000092.5	ENSP00000379866	P1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461024 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726818

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive Alport syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Apr 11, 2018

- -

Alport syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

May 06, 2021

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0103 - Loss of function is a known mechanism of disease for this gene and is associated with COL4A4-related nephropathy. Dominant negative is a suspected mechanism of disease for this gene as it is a structural protein (PMIDs: 12028435, 24046192). (I) 0108 - This gene is associated with both recessive and dominant disease. Alport syndrome typically has biallelic inheritance, although rare cases of monoallelic inheritance have been reported (PMID: 28704582). TBMN and focal segmental glomerulosclerosis (FSGS) are associated with autosomal dominant inheritance (OMIM, PMIDs: 16467446, 17942953). (I) 0200 - Variant is predicted to result in a missense amino acid change from glycine to aspartic acid. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0601 - Variant is located in the well-established functional triple repeat collegen domain affecting a glycine residue of a G-X-Y repeat (Uniprot). (SP) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been previously reported in multiple patients with Alport syndrome (ClinVar, LOVD, PMID: 24633401, 27281700, 33095447). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.73
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.55	D
Eigen	Pathogenic	0.75
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.2	H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-6.2	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.95		Loss of catalytic residue at P691 (P = 0.0722);
MVP		0.92
MPC		0.71
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.65
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: rs1553644402; hg19: chr2-227924932;