13-110211922-C-T

Variant names:

• chr13-110211922-C-T
• rs766346293
• NM_001845.6:c.388G>A

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PM5 PP3

The NM_001845.6(COL4A1):​c.388G>A​(p.Gly130Arg) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000000684 in 1,461,854 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G130W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL4A1 NM_001845.6 missense, splice_region
• Scores: Splicing: ADA: 0.9969
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 4.89
• 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: Ambry Genetics, Orphanet, G2P, Genomics England PanelApp
• autosomal dominant familial hematuria-retinal arteriolar tortuosity-contractures syndrome

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Genomics England PanelApp, Orphanet
• 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.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr13-110211922-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 2628039.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001845.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A1	NM_001845.6	MANE Select	c.388G>A	p.Gly130Arg	missense splice_region	Exon 7 of 52	NP_001836.3	P02462-1
	COL4A1	NM_001303110.2		c.388G>A	p.Gly130Arg	missense splice_region	Exon 7 of 25	NP_001290039.1	P02462-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A1	ENST00000375820.10	TSL:1 MANE Select	c.388G>A	p.Gly130Arg	missense splice_region	Exon 7 of 52	ENSP00000364979.4	P02462-1
	COL4A1	ENST00000543140.6	TSL:1	c.388G>A	p.Gly130Arg	missense splice_region	Exon 7 of 25	ENSP00000443348.1	P02462-2
	COL4A1	ENST00000650424.2		c.388G>A	p.Gly130Arg	missense splice_region	Exon 7 of 52	ENSP00000497477.2	A0A3B3ISV3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461854 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727228

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111990

Other (OTH) AF: 0.00 AC: 0 AN: 60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		4.9
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-6.0	D
REVEL	Pathogenic	0.96
Sift	Uncertain	0.0020	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.91		Gain of catalytic residue at C125 (P = 5e-04)
MVP		0.95
MPC		0.46
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.40
gMVP		1.0
Mutation Taster		=25/75	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.81
SpliceAI score (max)		0.28		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.28		Position offset: 0

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

Other links and lift over

dbSNP: rs766346293; hg19: chr13-110864269;