rs104886312

Positions:

• chrX-108591645-G-A
• chrX-108591645-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_033380.3(COL4A5):​c.1423+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000094 in 1,063,896 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. 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 Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 9.4e-7 (0 hom. 0 hem.)
• Consequence: COL4A5 NM_033380.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 8.71

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 Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.016351458 fraction of the gene. Cryptic splice site detected, with MaxEntScore 4.6, offset of -36, new splice context is: cagGTgata. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-108591645-G-A is Pathogenic according to our data. Variant chrX-108591645-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 2737333.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chrX-108591645-G-A is described in Lovd as [Pathogenic]. Variant chrX-108591645-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.1423+1G>A		splice_donor_variant, intron_variant		ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.1423+1G>A		splice_donor_variant, intron_variant		1	NM_033380.3	ENSP00000331902.7
COL4A5	ENST00000483338.1	c.247+1G>A		splice_donor_variant, intron_variant		1		ENSP00000495685.1
COL4A5	ENST00000361603.7	c.1423+1G>A		splice_donor_variant, intron_variant		2		ENSP00000354505.2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 9.40e-7 AC: 1 AN: 1063896 Hom.: 0 Cov.: 27 AF XY: 0.00 AC XY: 0 AN XY: 332148

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000285

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 30, 2023

This sequence change affects a donor splice site in intron 21 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). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with clinical features of Alport syndrome (PMID: 9848783, 30773290; Invitae). This variant is also known as 1625+1G>A. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	32
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	1.0	D
GERP RS		5.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs104886312; hg19: chrX-107834875;