rs1555303720

Variant names:

• chr13-110183010-C-T
• rs1555303720
• NM_001845.6:c.2078G>A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_001845.6(COL4A1):​c.2078G>A​(p.Gly693Glu) variant causes a missense change. 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. G693R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL4A1 NM_001845.6 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.19
• Publications: 0 publications found

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]

COL4A1 Gene-Disease associations (from GenCC):

• brain small vessel disease 1 with or without ocular anomalies

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: G2P, Ambry Genetics, PanelApp Australia, Orphanet, Genomics England PanelApp
• autosomal dominant familial hematuria-retinal arteriolar tortuosity-contractures syndrome

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Ambry Genetics
• microangiopathy and leukoencephalopathy, pontine, autosomal dominant

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• familial porencephaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• pontine autosomal dominant microangiopathy with leukoencephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• retinal arterial tortuosity

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• muscular dystrophy-dystroglycanopathy, type A

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 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, 11 uncertain in NM_001845.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-110183011-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2694589.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.972
• PP5: Variant 13-110183010-C-T is Pathogenic according to our data. Variant chr13-110183010-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 434810.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A1	NM_001845.6	c.2078G>A	p.Gly693Glu	missense_variant	Exon 28 of 52	ENST00000375820.10	NP_001836.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A1	ENST00000375820.10	c.2078G>A	p.Gly693Glu	missense_variant	Exon 28 of 52	1	NM_001845.6	ENSP00000364979.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Brain small vessel disease 1 with or without ocular anomalies Pathogenic:1

Aug 27, 2015

Genetic Services Laboratory, University of Chicago

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal dominant familial hematuria-retinal arteriolar tortuosity-contractures syndrome Pathogenic:1

May 30, 2023

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Criteria applied: PM1_STR,PS4_SUP,PM2_SUP,PP3 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.91	D
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.3	H
PhyloP100		7.2
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.74		Gain of catalytic residue at P694 (P = 0);
MVP		0.99
MPC		0.53
ClinPred		1.0	D
GERP RS		3.9
Varity_R		0.94
gMVP		1.0
Mutation Taster		=7/93	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: rs1555303720; hg19: chr13-110835357;