chrX-108157174-G-C

Position:

• chrX-108157174-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_033641.4(COL4A6):​c.4899C>G​(p.Ile1633Met) 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 pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: COL4A6 NM_033641.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.354

Genes affected

COL4A6 (HGNC:2208): (collagen type IV alpha 6 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. 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, alpha 5 type IV collagen, so that the gene pair shares a common promoter. Deletions in the alpha 5 gene that extend into the alpha 6 gene result in diffuse leiomyomatosis accompanying the X-linked Alport syndrome caused by the deletion in the alpha 5 gene. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Dec 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.812

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL4A6	NM_033641.4	c.4899C>G	p.Ile1633Met	missense_variant	45/45	ENST00000334504.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL4A6	ENST00000334504.12	c.4899C>G	p.Ile1633Met	missense_variant	45/45	5	NM_033641.4	P4

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 13, 2021

This sequence change replaces isoleucine with methionine at codon 1634 of the COL4A6 protein (p.Ile1634Met). The isoleucine residue is moderately conserved and there is a small physicochemical difference between isoleucine and methionine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with COL4A6-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Benign	15
DANN	Benign	0.90
DEOGEN2	Uncertain	0.75	.;D;.;.;D;D
FATHMM_MKL	Benign	0.63	D
LIST_S2	Uncertain	0.97	D;D;D;D;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.81	D;D;D;D;D;D
MetaSVM	Pathogenic	0.82	D
MutationAssessor	Uncertain	2.0	.;M;.;.;.;.
MutationTaster	Benign	0.80	D;D;D;D;D;D
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-3.0	D;D;.;D;.;.
REVEL	Pathogenic	0.66
Sift	Pathogenic	0.0	D;D;.;D;.;.
Sift4G	Uncertain	0.0020	D;D;D;D;D;D
Polyphen		1.0	D;D;.;D;.;.
Vest4		0.60
MutPred		0.74		.;Loss of glycosylation at S1637 (P = 0.0808);.;.;.;.;
MVP		0.91
MPC		0.33
ClinPred		0.91	D
GERP RS		-1.1
Varity_R		0.65
gMVP		0.82

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

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-107400404;