2-227289222-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_000091.5(COL4A3):c.2954G>T(p.Gly985Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000411 in 1,461,548 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).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: COL4A3 NM_000091.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:2
• Conservation: PhyloP100: 5.70

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 2-227289222-G-T is Pathogenic according to our data. Variant chr2-227289222-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 17490.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=2}. Variant chr2-227289222-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL4A3	NM_000091.5	c.2954G>T	p.Gly985Val	missense_variant	35/52	ENST00000396578.8
MFF-DT	NR_102371.1	n.244-7433C>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL4A3	ENST00000396578.8	c.2954G>T	p.Gly985Val	missense_variant	35/52	1	NM_000091.5	P1
MFF-DT	ENST00000439598.6	n.244-7433C>A		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.0000201 AC: 5 AN: 248976 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135088

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

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: 0.000165

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461548 Hom.: 0 Cov.: 30 AF XY: 0.00000275 AC XY: 2 AN XY: 727066

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000895

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: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Sep 21, 2023	This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 985 of the COL4A3 protein (p.Gly985Val). This variant is present in population databases (rs121912827, gnomAD 0.01%). This missense change has been observed in individuals with Clinical features of Alport syndrome (PMID: 11961012, 25307543). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 17490). 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) performed at Invitae indicates that this missense variant is expected to disrupt COL4A3 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Apr 19, 2023	In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Affects a glycine residue in a Gly-X-Y motif in the triple helical region of the COL4A3 gene; This variant is associated with the following publications: (PMID: 11961012, 33838161) -

Autosomal recessive Alport syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

May 23, 2018

- -

Benign familial hematuria Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

May 01, 2002

- -

Alport syndrome Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Apr 07, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.56
Cadd	Uncertain	25
Dann	Uncertain	0.98
DEOGEN2	Uncertain	0.68	D;.
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.4	H;.
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-7.5	D;D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.94
MutPred		1.0		Gain of ubiquitination at K984 (P = 0.0964);.;
MVP		0.97
MPC		0.24
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.99
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.18		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: rs121912827; hg19: chr2-228153938;