rs1555304112

Positions:

• chr13-110186463-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 7P and 1B. PM1 PM2 PP2 PP3_Moderate BS2_Supporting

The NM_001845.6(COL4A1):​c.1819G>C​(p.Gly607Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000342 in 1,461,464 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G607V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: COL4A1 NM_001845.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.97

Genes affected

COL4A1 (HGNC:2202): (collagen type IV alpha 1 chain) This gene encodes a type IV collagen alpha protein. Type IV collagen proteins are integral components of basement membranes. This gene shares a bidirectional promoter with a paralogous gene on the opposite strand. The protein consists of an amino-terminal 7S domain, a triple-helix forming collagenous domain, and a carboxy-terminal non-collagenous domain. It functions as part of a heterotrimer and interacts with other extracellular matrix components such as perlecans, proteoglycans, and laminins. In addition, proteolytic cleavage of the non-collagenous carboxy-terminal domain results in a biologically active fragment known as arresten, which has anti-angiogenic and tumor suppressor properties. Mutations in this gene cause porencephaly, cerebrovascular disease, and renal and muscular defects. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 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, 5 uncertain in NM_001845.6
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL4A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.932
• BS2: High AC in GnomAdExome4 at 5 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL4A1	NM_001845.6	c.1819G>C	p.Gly607Arg	missense_variant	26/52	ENST00000375820.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL4A1	ENST00000375820.10	c.1819G>C	p.Gly607Arg	missense_variant	26/52	1	NM_001845.6	P1
COL4A1	ENST00000649738.1	n.1949G>C		non_coding_transcript_exon_variant	26/31

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461464 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 727026

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Nov 28, 2016

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 08, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 434811). This variant has not been reported in the literature in individuals affected with COL4A1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 607 of the COL4A1 protein (p.Gly607Arg). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	0.68
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.77	T
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.6	H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.0	D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.025	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.51		Gain of catalytic residue at Y608 (P = 0);
MVP		0.94
MPC		1.3
ClinPred		1.0	D
GERP RS		4.1
Varity_R		0.14
gMVP		0.94

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: rs1555304112; hg19: chr13-110838810; COSMIC: COSV65423132; COSMIC: COSV65423132;