chr2-227238007-GGG-CGA

Position:

• chr2-227238007-GGG-CGA

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP6_Moderate

The NM_000091.5(COL4A3):​c.127_129delGGGinsCGA​(p.Gly43Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely benign (★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Benign in Lovd.

• Frequency: Genomes: not found (cov: 31)
• Consequence: COL4A3 NM_000091.5 missense
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 2.42

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]

MFF-DT (HGNC:41067): (MFF divergent transcript)

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP6: Variant 2-227238007-GGG-CGA is Benign according to our data. Variant chr2-227238007-GGG-CGA is described in ClinVar as [Likely_benign]. Clinvar id is 3233713.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL4A3	NM_000091.5	c.127_129delGGGinsCGA	p.Gly43Arg	missense_variant		ENST00000396578.8	NP_000082.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL4A3	ENST00000396578.8	c.127_129delGGGinsCGA	p.Gly43Arg	missense_variant		1	NM_000091.5	ENSP00000379823.3

Frequencies

GnomAD3 genomes Cov.: 31

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Mar 28, 2024

Variant summary: COL4A3 c.127_129delinsCGA (p.Gly43Arg) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. Another variant resulting in the same amino acid change was found at a frequency of 0.29 in 280794 control chromosomes in the gnomAD database, including 13253 homozygotes. The observed variant frequency is approximately 200 fold of the estimated maximal expected allele frequency for a pathogenic variant in COL4A3 causing Alport Syndrome, Autosomal Recessive phenotype (0.0014), strongly suggesting that the variant is benign. To our knowledge, no occurrence of c.127_129delinsCGA in individuals affected with Alport Syndrome, Autosomal Recessive and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-228102723;