Genetic Variant COL4A3:p.Lys34LeufsTer2 (chr2-227237970-T-TTGTG) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000091.5(COL4A3):c.92_95dupGTGT(p.Lys34LeufsTer2) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000275 in 1,457,146 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

COL4A3
NM_000091.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 3.73

Variant links:

Genes affected

COL4A3 (HGNC:2204): (collagen type IV alpha 3 chain) Type IV collagen, the major structural component of basement membranes, is a multimeric protein composed of 3 alpha subunits. These subunits are encoded by 6 different genes, alpha 1 through alpha 6, each of which can form a triple helix structure with 2 other subunits to form type IV collagen. This gene encodes alpha 3. In the Goodpasture syndrome, autoantibodies bind to the collagen molecules in the basement membranes of alveoli and glomeruli. The epitopes that elicit these autoantibodies are localized largely to the non-collagenous C-terminal domain of the protein. A specific kinase phosphorylates amino acids in this same C-terminal region and the expression of this kinase is upregulated during pathogenesis. This gene is also linked to an autosomal recessive form of Alport syndrome. The mutations contributing to this syndrome are also located within the exons that encode this C-terminal region. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter. [provided by RefSeq, Jun 2010]

COL4A3 links:

MFF-DT (HGNC:41067): (MFF divergent transcript)

MFF-DT links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 198 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-227237970-T-TTGTG is Pathogenic according to our data. Variant chr2-227237970-T-TTGTG is described in ClinVar as [Pathogenic]. Clinvar id is 1075091.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
COL4A3	NM_000091.5 link	c.92_95dupGTGT	p.Lys34LeufsTer2	frameshift_variant	Exon 2 of 52	ENST00000396578.8	NP_000082.2	Q01955-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A3	ENST00000396578.8 link	c.92_95dupGTGT	p.Lys34LeufsTer2	frameshift_variant	Exon 2 of 52	1	NM_000091.5	ENSP00000379823.3		Q01955-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000801

AC:

AN:

249536

Hom.:

AF XY:

0.00000739

AC XY:

AN XY:

135380

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000275

AC:

AN:

1457146

Hom.:

Cov.:

AF XY:

0.00000414

AC XY:

AN XY:

725234

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

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:

0.00000181

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Aug 24, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This premature translational stop signal has been observed in individual(s) with clinical features of Alport syndrome and thin basement membrane nephropathy (PMID: 25307543). This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change creates a premature translational stop signal (p.Lys34Leufs*2) in the COL4A3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in COL4A3 are known to be pathogenic (PMID: 8956999, 24854265, 26809805, 27281700). -

Alport syndrome

Pathogenic:1

Oct 06, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Benign familial hematuria;C4746745:Autosomal recessive Alport syndrome;C5882663:Autosomal dominant Alport syndrome

Pathogenic:1

Aug 15, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over