NM_001845.6:c.2842G>A

Variant names:

• chr13-110176912-C-T
• rs1555303073
• NM_001845.6:c.2842G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM2 PM5 PP3_Strong PP5_Moderate

The NM_001845.6(COL4A1):​c.2842G>A​(p.Gly948Ser) 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 Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G948R) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL4A1 NM_001845.6 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.40
• Publications: 1 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 10 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-110176912-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 864857.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 13-110176912-C-T is Pathogenic according to our data. Variant chr13-110176912-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 496641.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A1	NM_001845.6	c.2842G>A	p.Gly948Ser	missense_variant	Exon 34 of 52	ENST00000375820.10	NP_001836.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A1	ENST00000375820.10	c.2842G>A	p.Gly948Ser	missense_variant	Exon 34 of 52	1	NM_001845.6	ENSP00000364979.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

Alfa AF: 0.000259 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Optic nerve hypoplasia Pathogenic:1

Feb 14, 2018

Rare Disease Group, Clinical Genetics, Karolinska Institutet

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

The specific variant has previously been seen in schizencephaly with epilepsy and cerebral palsy, and other variants in COL4A1 in a number of studies have been seen in optic nerve hypoplasia. This individual has optic nerve hypoplasia, epilepsy and cerebral palsy, consistent with the phenotype seen in other individuals with missense variants in COL4A1. Also, the variant is de novo. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	3.8	H
PhyloP100		5.4
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0090	D
Polyphen		1.0	D
Vest4		0.75
MutPred		0.88		Gain of catalytic residue at M943 (P = 0.011);
MVP		0.98
MPC		0.39
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.47
gMVP		1.0
Mutation Taster		=2/98	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: rs1555303073; hg19: chr13-110829259;