2-227266473-G-C

Position:

• chr2-227266473-G-C

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PS1_Moderate PM1 PM2 PM5 PP3_Strong PP5

The ENST00000396578.8(COL4A3):​c.1372G>C​(p.Gly458Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,768 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G458E) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: COL4A3 ENST00000396578.8 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:1
• Conservation: PhyloP100: 5.96

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]

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

ACMG classification

Verdict is Pathogenic. Variant got 13 ACMG points.

• PS1: Transcript ENST00000396578.8 (COL4A3) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar as 1355638
• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 4 uncertain in ENST00000396578.8
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-227266474-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1068322.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989
• PP5: Variant 2-227266473-G-C is Pathogenic according to our data. Variant chr2-227266473-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 447166.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A3	NM_000091.5	c.1372G>C	p.Gly458Arg	missense_variant	22/52	ENST00000396578.8	NP_000082.2
MFF-DT	NR_102371.1	n.656-538C>G		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A3	ENST00000396578.8	c.1372G>C	p.Gly458Arg	missense_variant	22/52	1	NM_000091.5	ENSP00000379823	P1
MFF-DT	ENST00000439598.6	n.656-538C>G		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000241 AC: 6 AN: 249378 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135320

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000174

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461768 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727176

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000157

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:2 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 14, 2023	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Gly458 amino acid residue in COL4A3. Other variant(s) that disrupt this residue have been observed in individuals with COL4A3-related conditions (Invitae), which suggests that this may be a clinically significant amino acid residue. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on COL4A3 protein function. ClinVar contains an entry for this variant (Variation ID: 447166). This missense change has been observed in individuals with clinical features of autosomal dominant Alport syndrome (Invitae). It has also been observed to segregate with disease in related individuals. This variant is present in population databases (rs757341933, gnomAD 0.02%). This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 458 of the COL4A3 protein (p.Gly458Arg). -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Feb 23, 2023	Affects a glycine residue in a Gly-X-Y motif in the triple helical region of the COL4A3 gene; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Likely pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Feb 10, 2020	The variant disrupts a glycine residue in the canonical Gly-X-Y repeats of the triple helix domain, which are required for stability and structure of this protein. Therefore it is expected to severely affect the function of the protein. The frequency of this variant in the general population is consistent with pathogenicity. -

COL4A3-related disorder Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 25, 2024

The COL4A3 c.1372G>C variant is predicted to result in the amino acid substitution p.Gly458Arg. The p.Gly458Arg variant affects a Gly residue of the conserved triple helical domain, where substitutions of the glycine are usually pathogenic (Hudson et al. 1993. PubMed ID: 8253711; https://www.ncbi.nlm.nih.gov/books/NBK21582/). This variant has been reported in a patient tested using a panel for chronic renal disease (Bleyer et al., 2022. PubMed ID: 35325889, Table S3). At PreventionGenetics, we have observed this variant in other unrelated patients with features of COL4A3-related disorders (internal data). This variant is reported in 0.017% of alleles in individuals of Latino descent in gnomAD. This variant is interpreted as likely pathogenic. -

Benign familial hematuria;C4746745:Autosomal recessive Alport syndrome;C5882663:Autosomal dominant Alport syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.77
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.55
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.0	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-5.6	D
REVEL	Pathogenic	0.88
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.78		Gain of solvent accessibility (P = 6e-04);
MVP		0.96
MPC		0.83
ClinPred		0.99	D
GERP RS		5.7
Varity_R		0.93
gMVP		0.95

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

Publications

LitVar

Other links and lift over

dbSNP: rs757341933; hg19: chr2-228131189;