chrX-108571468-T-C

Variant names:

• chrX-108571468-T-C
• rs281874738
• NM_033380.3:c.438+2T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_033380.3(COL4A5):​c.438+2T>C variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: COL4A5 NM_033380.3 splice_donor, intron
• Scores: Splicing: ADA: 0.9940
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.72
• Publications: 2 publications found

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]

COL4A5 Gene-Disease associations (from GenCC):

• Alport syndrome

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen, G2P
• X-linked Alport syndrome

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Genomics England PanelApp, Myriad Women’s Health, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.010638298 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-108571468-T-C is Pathogenic according to our data. Variant chrX-108571468-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3391289.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A5	NM_033380.3	c.438+2T>C		splice_donor_variant, intron_variant	Intron 7 of 52	ENST00000328300.11	NP_203699.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A5	ENST00000328300.11	c.438+2T>C		splice_donor_variant, intron_variant	Intron 7 of 52	1	NM_033380.3	ENSP00000331902.7
COL4A5	ENST00000361603.7	c.438+2T>C		splice_donor_variant, intron_variant	Intron 7 of 50	2		ENSP00000354505.2

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 22

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

X-linked Alport syndrome Pathogenic:1

Jul 22, 2023

Neuberg Centre For Genomic Medicine, NCGM

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The observed invariant splice donor c.438+2T>C variant in COL4A5 gene has been reported previously in an individual affected with Alport syndrome Ma et al., 2011. The c.438+2T>C variant is absent in gnomAD Exomes. This variant has not been submitted to the ClinVar database. The SpliceAI predicts a score of 0.83 for this variant. Loss of function variants have been previously reported to be disease causing. However, additional functional studies will be required to prove the pathogenicity of this variant. For these reasons, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	26
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		6.7
GERP RS		6.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.99
dbscSNV1_RF	Benign	0.65
SpliceAI score (max)		0.83		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.83		Position offset: -2

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

Other links and lift over

dbSNP: rs281874738; hg19: chrX-107814698;