2-227164714-G-C

Position:

• chr2-227164714-G-C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS2

The NM_000091.5(COL4A3):​c.-13G>C variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00135 in 1,529,732 control chromosomes in the GnomAD database, including 9 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0020 (3 hom., cov: 32)
  • Exomes 𝑓: 0.0013 (6 hom.)
• Consequence: COL4A3 NM_000091.5 5_prime_UTR
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 0.346

Genes affected

COL4A3 (HGNC:2204): (collagen type IV alpha 3 chain) Type IV collagen, the major structural component of basement membranes, is a multimeric protein composed of 3 alpha subunits. These subunits are encoded by 6 different genes, alpha 1 through alpha 6, each of which can form a triple helix structure with 2 other subunits to form type IV collagen. This gene encodes alpha 3. In the Goodpasture syndrome, autoantibodies bind to the collagen molecules in the basement membranes of alveoli and glomeruli. The epitopes that elicit these autoantibodies are localized largely to the non-collagenous C-terminal domain of the protein. A specific kinase phosphorylates amino acids in this same C-terminal region and the expression of this kinase is upregulated during pathogenesis. This gene is also linked to an autosomal recessive form of Alport syndrome. The mutations contributing to this syndrome are also located within the exons that encode this C-terminal region. 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. [provided by RefSeq, Jun 2010]

COL4A3 (HGNC:):

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.81).
• BP6: Variant 2-227164714-G-C is Benign according to our data. Variant chr2-227164714-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 334752.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
• BS2: High Homozygotes in GnomAd4 at 3 SD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A3	NM_000091.5	c.-13G>C		5_prime_UTR_variant	1/52	ENST00000396578.8	NP_000082.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A3	ENST00000396578	c.-13G>C		5_prime_UTR_variant	1/52	1	NM_000091.5	ENSP00000379823.3

Frequencies

GnomAD3 genomes AF: 0.00204 AC: 309 AN: 151722 Hom.: 3 Cov.: 32

Gnomad AFR AF: 0.000291

Gnomad AMI AF: 0.00220

Gnomad AMR AF: 0.000983

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00104

Gnomad FIN AF: 0.0177

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00122

Gnomad OTH AF: 0.00240

GnomAD3 exomes AF: 0.00110 AC: 138 AN: 125592 Hom.: 1 AF XY: 0.00115 AC XY: 79 AN XY: 68848

Gnomad AFR exome AF: 0.000184

Gnomad AMR exome AF: 0.000165

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000900

Gnomad FIN exome AF: 0.0129

Gnomad NFE exome AF: 0.000844

Gnomad OTH exome AF: 0.00128

GnomAD4 exome AF: 0.00128 AC: 1757 AN: 1377898 Hom.: 6 Cov.: 31 AF XY: 0.00132 AC XY: 899 AN XY: 679960

Gnomad4 AFR exome AF: 0.000129

Gnomad4 AMR exome AF: 0.000309

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000976

Gnomad4 FIN exome AF: 0.0138

Gnomad4 NFE exome AF: 0.00107

Gnomad4 OTH exome AF: 0.000869

GnomAD4 genome AF: 0.00204 AC: 309 AN: 151834 Hom.: 3 Cov.: 32 AF XY: 0.00276 AC XY: 205 AN XY: 74216

Gnomad4 AFR AF: 0.000290

Gnomad4 AMR AF: 0.000982

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00104

Gnomad4 FIN AF: 0.0177

Gnomad4 NFE AF: 0.00122

Gnomad4 OTH AF: 0.00237

Alfa AF: 0.00111 Hom.: 0

Bravo AF: 0.000914

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Alport syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 09, 2018

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
CADD	Benign	9.0
DANN	Benign	0.65

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

Publications

LitVar

Other links and lift over

dbSNP: rs770803750; hg19: chr2-228029430;