13-110306975-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_001845.6(COL4A1):c.53T>C(p.Leu18Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: COL4A1 NM_001845.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.07

Genes affected

COL4A1 (HGNC:2202): (collagen type IV alpha 1 chain) This gene encodes a type IV collagen alpha protein. Type IV collagen proteins are integral components of basement membranes. This gene shares a bidirectional promoter with a paralogous gene on the opposite strand. The protein consists of an amino-terminal 7S domain, a triple-helix forming collagenous domain, and a carboxy-terminal non-collagenous domain. It functions as part of a heterotrimer and interacts with other extracellular matrix components such as perlecans, proteoglycans, and laminins. In addition, proteolytic cleavage of the non-collagenous carboxy-terminal domain results in a biologically active fragment known as arresten, which has anti-angiogenic and tumor suppressor properties. Mutations in this gene cause porencephaly, cerebrovascular disease, and renal and muscular defects. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

COL4A2 (HGNC:2203): (collagen type IV alpha 2 chain) This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. The C-terminal portion of the protein, known as canstatin, is an inhibitor of angiogenesis and tumor growth. 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, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL4A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.834

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL4A1	NM_001845.6	c.53T>C	p.Leu18Pro	missense_variant	1/52	ENST00000375820.10
COL4A1	NM_001303110.2	c.53T>C	p.Leu18Pro	missense_variant	1/25

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL4A1	ENST00000375820.10	c.53T>C	p.Leu18Pro	missense_variant	1/52	1	NM_001845.6	P1
COL4A1	ENST00000543140.6	c.53T>C	p.Leu18Pro	missense_variant	1/25	1
COL4A2	ENST00000400163.7	c.-44-885A>G		intron_variant		5
COL4A1	ENST00000649738.1	n.183T>C		non_coding_transcript_exon_variant	1/31

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1324772 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 652734

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 31, 2024

The c.53T>C (p.L18P) alteration is located in exon 1 (coding exon 1) of the COL4A1 gene. This alteration results from a T to C substitution at nucleotide position 53, causing the leucine (L) at amino acid position 18 to be replaced by a proline (P). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.040
Cadd	Uncertain	24
Dann	Benign	0.82
DEOGEN2	Uncertain	0.50	T;.
Eigen	Benign	0.16
Eigen_PC	Benign	0.14
FATHMM_MKL	Benign	0.48	N
LIST_S2	Benign	0.45	T;T
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.83	D;D
MetaSVM	Uncertain	0.14	D
MutationAssessor	Benign	0.34	N;N
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.91	D
PROVEAN	Benign	-2.0	N;N
REVEL	Pathogenic	0.74
Sift	Benign	0.28	T;T
Sift4G	Benign	0.068	T;D
Polyphen		0.99	D;.
Vest4		0.61
MutPred		0.66		Gain of loop (P = 0.0045);Gain of loop (P = 0.0045);
MVP		0.93
MPC		0.63
ClinPred		0.37	T
GERP RS		3.3
Varity_R		0.46
gMVP		0.61

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr13-110959322;