rs1556462917

Variant names:

• chrX-108694806-G-A
• NM_033380.3:c.4707-1G>A

Your query was ambiguous. Multiple possible variants found:

• chrX-108694806-G-A
• chrX-108694806-G-C
• chrX-108694806-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_033380.3(COL4A5):​c.4707-1G>A variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: COL4A5 NM_033380.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 10.0

Genes affected

COL4A5 (HGNC:2207): (collagen type IV alpha 5 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. Mutations in this gene are associated with X-linked Alport syndrome, also known as hereditary nephritis. 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. Alternatively spliced transcript variants have been identified for this gene. [provided by RefSeq, Aug 2010]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.6, offset of 8, new splice context is: ttcctttaccaaatgtgcAGtat. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-108694806-G-A is Pathogenic according to our data. Variant chrX-108694806-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1994581.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-108694806-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.4707-1G>A		splice_acceptor_variant, intron_variant	Intron 50 of 52	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.4707-1G>A		splice_acceptor_variant, intron_variant	Intron 50 of 52	1	NM_033380.3	ENSP00000331902.7

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 23

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

May 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. Disruption of this splice site has been observed in individual(s) with Alport syndrome (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 48 of the COL4A5 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in COL4A5 are known to be pathogenic (PMID: 9195222, 10752524, 14514738, 24854265, 26809805). -

X-linked Alport syndrome Pathogenic:1

Dec 22, 2022

Breakthrough Genomics, Breakthrough Genomics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This intronic variant, c.4707-1G>A, lies in the essential splice acceptor site, in intron 50 of the COL4A5 gene. In silico splice prediction tools (ASSP and NNSPLICE) indicate that this variant will affect splicing due to the loss of constitutive splice site and introduction of a new splice site, which in turn might lead to a frameshift and consequent premature termination of the protein; this will likely result in loss-of-function. The variant seems to be novel, as it has not been previously reported in population or public databases or in the literature. However, a different variant at the same splice site, c.4707-1G>C has been reported as pathogenic in the ClinVar database, suggesting variants affecting this splice site will impact protein function. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	32
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.6

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.90		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.90		Position offset: 1

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-107938036;