chr2-227263852-G-T

Variant names:

• chr2-227263852-G-T
• rs34505188
• NM_000091.5:c.1223G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000091.5(COL4A3):​c.1223G>T​(p.Arg408Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R408C) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL4A3 NM_000091.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.914
• Publications: 30 publications found

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

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 3 uncertain in NM_000091.5
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.09181565).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000091.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A3	NM_000091.5	MANE Select	c.1223G>T	p.Arg408Leu	missense	Exon 21 of 52	NP_000082.2
	MFF-DT	NR_102371.1		n.1486+817C>A		intron	N/A

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A3	ENST00000396578.8	TSL:1 MANE Select	c.1223G>T	p.Arg408Leu	missense	Exon 21 of 52	ENSP00000379823.3
	MFF-DT	ENST00000439598.6	TSL:1	n.1486+817C>A		intron	N/A
	MFF-DT	ENST00000396588.6	TSL:2	n.1552+817C>A		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 1422

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.072
BayesDel_addAF	Benign	-0.059	T
BayesDel_noAF	Benign	-0.32
CADD	Benign	9.2
DANN	Benign	0.56
DEOGEN2	Benign	0.26	T
Eigen	Benign	-0.92
Eigen_PC	Benign	-0.75
FATHMM_MKL	Benign	0.52	D
LIST_S2	Benign	0.18	T
M_CAP	Uncertain	0.12	D
MetaRNN	Benign	0.092	T
MetaSVM	Benign	-0.61	T
MutationAssessor	Benign	-0.59	N
PhyloP100		0.91
PrimateAI	Benign	0.27	T
PROVEAN	Benign	-0.040	N
REVEL	Benign	0.18
Sift	Benign	0.70	T
Sift4G	Benign	0.33	T
Polyphen		0.077	B
Vest4		0.094
MutPred		0.47		Loss of methylation at R408 (P = 0.0217)
MVP		0.65
MPC		0.28
ClinPred		0.14	T
GERP RS		2.1
Varity_R		0.071
gMVP		0.22
Mutation Taster		=93/7	polymorphism

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

Other links and lift over

dbSNP: rs34505188; hg19: chr2-228128568;