rs281865426

Variant names:

• chr13-110187292-CC-AA
• rs281865426
• NM_001845.6:c.1573_1574delGGinsTT

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM5 PP5

The NM_001845.6(COL4A1):​c.1573_1574delGGinsTT​(p.Gly525Leu) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G525R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL4A1 NM_001845.6 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 7.19
• Publications: 6 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: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_001845.6
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-110187293-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2576606.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP5: Variant 13-110187292-CC-AA is Pathogenic according to our data. Variant chr13-110187292-CC-AA is described in ClinVar as Pathogenic. ClinVar VariationId is 18464.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A1	NM_001845.6	c.1573_1574delGGinsTT	p.Gly525Leu	missense_variant		ENST00000375820.10	NP_001836.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A1	ENST00000375820.10	c.1573_1574delGGinsTT	p.Gly525Leu	missense_variant		1	NM_001845.6	ENSP00000364979.4

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

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

Oct 01, 2010

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.2
Mutation Taster		=9/91	disease causing

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs281865426; hg19: chr13-110839639;