rs932962404

Variant names:

• chr2-227089866-G-A
• rs932962404
• NM_000092.5:c.1459+2C>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_000092.5(COL4A4):​c.1459+2C>T variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,610,738 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 28)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: COL4A4 NM_000092.5 splice_donor, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.01
• Publications: 0 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: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, Orphanet, Ambry Genetics, Myriad Women’s Health
• Alport syndrome

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

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.017740982 fraction of the gene. Cryptic splice site detected, with MaxEntScore 11, offset of 0 (no position change), new splice context is: aagGTaagt. 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL4A4	NM_000092.5	c.1459+2C>T		splice_donor_variant, intron_variant	Intron 21 of 47	ENST00000396625.5	NP_000083.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL4A4	ENST00000396625.5	c.1459+2C>T		splice_donor_variant, intron_variant	Intron 21 of 47	5	NM_000092.5	ENSP00000379866.3

Frequencies

GnomAD3 genomes AF: 0.00000659 AC: 1 AN: 151822 Hom.: 0 Cov.: 28

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249384 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000206 AC: 3 AN: 1458916 Hom.: 0 Cov.: 28 AF XY: 0.00000275 AC XY: 2 AN XY: 726018

⚠️ 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: 33420

American (AMR) AF: 0.00 AC: 0 AN: 44710

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.00 AC: 0 AN: 39670

South Asian (SAS) AF: 0.00 AC: 0 AN: 86192

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53390

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1109326

Other (OTH) AF: 0.00 AC: 0 AN: 60328

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00400497), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000659 AC: 1 AN: 151822 Hom.: 0 Cov.: 28 AF XY: 0.00 AC XY: 0 AN XY: 74102

African (AFR) AF: 0.00 AC: 0 AN: 41330

American (AMR) AF: 0.00 AC: 0 AN: 15226

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5148

South Asian (SAS) AF: 0.00 AC: 0 AN: 4810

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10524

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68004

Other (OTH) AF: 0.00 AC: 0 AN: 2082

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Dec 21, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1459+2C>T variant in COL4A4 has not been previously reported in individual s with hearing loss or Alport syndrome, but has been identified in 1/111608 Euro pean chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broad institute.org/; dbSNP rs932962404). Although this variant has been seen in the g eneral population, its frequency is not high enough to rule out a pathogenic rol e. This variant occurs in the invariant region (+/- 1/2) of the splice consensus sequence but computational tools do not suggest an impact to splicing. However, this information is not predictive enough to rule out pathogenicity. In summary , the clinical significance of the c.1459+2C>T variant is uncertain. ACMG/AMP Cr iteria applied: PM2. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.040
CADD	Benign	20
DANN	Benign	0.95
Eigen	Pathogenic	0.79
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Benign	0.72	D
PhyloP100		1.0
GERP RS		3.9
Mutation Taster		=21/79	disease causing

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: rs932962404; hg19: chr2-227954582;