2-227240188-G-A

Position:

• chr2-227240188-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000091.5(COL4A3):​c.190G>A​(p.Gly64Arg) 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL4A3 NM_000091.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 4.99

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 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL4A3	NM_000091.5	c.190G>A	p.Gly64Arg	missense_variant	3/52	ENST00000396578.8
MFF-DT	NR_102371.1	n.1593-2014C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL4A3	ENST00000396578.8	c.190G>A	p.Gly64Arg	missense_variant	3/52	1	NM_000091.5	P1
MFF-DT	ENST00000439598.6	n.1593-2014C>T		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
CADD	Pathogenic	31
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.68	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	4.2	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.74	T
PROVEAN	Pathogenic	-6.9	D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0020	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.98		Loss of glycosylation at K63 (P = 0.0621);
MVP		0.97
MPC		0.83
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.97
gMVP		0.96

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: rs917643323; hg19: chr2-228104904; COSMIC: COSV67414535;