rs121912862

Variant names:

• chr2-227007475-G-T
• rs121912862
• NM_000092.5:c.4923C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_000092.5(COL4A4):​c.4923C>A​(p.Cys1641*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,878 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL4A4 NM_000092.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 0.975
• Publications: 1 publications found

Genes affected

COL4A4 (HGNC:2206): (collagen type IV alpha 4 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. This particular collagen IV subunit, however, is only found in a subset 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 so that each gene pair shares a common promoter. Mutations in this gene are associated with type II autosomal recessive Alport syndrome (hereditary glomerulonephropathy) and with familial benign hematuria (thin basement membrane disease). Two transcripts, differing only in their transcription start sites, have been identified for this gene and, as is common for collagen genes, multiple polyadenylation sites are found in the 3' UTR. [provided by RefSeq, Jul 2008]

COL4A4 Gene-Disease associations (from GenCC):

• autosomal recessive Alport syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Myriad Women’s Health, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• Alport syndrome

  Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen
• hematuria, benign familial, 1

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
• autosomal dominant Alport syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 18 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-227007475-G-T is Pathogenic according to our data. Variant chr2-227007475-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 17408.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000092.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A4	NM_000092.5	MANE Select	c.4923C>A	p.Cys1641*	stop_gained	Exon 48 of 48	NP_000083.3	P53420

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL4A4	ENST00000396625.5	TSL:5 MANE Select	c.4923C>A	p.Cys1641*	stop_gained	Exon 48 of 48	ENSP00000379866.3	P53420
	COL4A4	ENST00000682098.1		c.525C>A	p.Cys175*	stop_gained	Exon 3 of 3	ENSP00000508331.1	A0A804HLF6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461878 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 727234

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Autosomal recessive Alport syndrome (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	37
DANN	Uncertain	0.99
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.43
FATHMM_MKL	Uncertain	0.85	D
PhyloP100		0.97
Vest4		0.69
GERP RS		2.6
Mutation Taster		=4/196	disease causing (ClinVar)

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: rs121912862; hg19: chr2-227872191;