rs765702033

Positions:

• chr6-75142136-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The ENST00000322507.13(COL12A1):​c.4853G>T​(p.Ser1618Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,816 control chromosomes in the GnomAD database, with no homozygous occurrence. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: COL12A1 ENST00000322507.13 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.273

Genes affected

COL12A1 (HGNC:2188): (collagen type XII alpha 1 chain) This gene encodes the alpha chain of type XII collagen, a member of the FACIT (fibril-associated collagens with interrupted triple helices) collagen family. Type XII collagen is a homotrimer found in association with type I collagen, an association that is thought to modify the interactions between collagen I fibrils and the surrounding matrix. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), COL12A1. . Gene score misZ 2.106 (greater than the threshold 3.09). Trascript score misZ 3.5535 (greater than threshold 3.09). GenCC has associacion of gene with Bethlem myopathy, Bethlem myopathy 2, Ullrich congenital muscular dystrophy 2, Ullrich congenital muscular dystrophy.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL12A1	NM_004370.6	c.4853G>T	p.Ser1618Ile	missense_variant	27/66	ENST00000322507.13	NP_004361.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL12A1	ENST00000322507.13	c.4853G>T	p.Ser1618Ile	missense_variant	27/66	1	NM_004370.6	ENSP00000325146	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249410 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135302

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461816 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 727214

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000826 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 2;C4225314:Ullrich congenital muscular dystrophy 2 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 22, 2024

This sequence change replaces serine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 1618 of the COL12A1 protein (p.Ser1618Ile). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with COL12A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 579127). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt COL12A1 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.0099	T
BayesDel_noAF	Benign	-0.25
CADD	Benign	21
DANN	Uncertain	0.99
DEOGEN2	Benign	0.10	T;T;.;.;.
Eigen	Benign	0.045
Eigen_PC	Benign	-0.025
FATHMM_MKL	Benign	0.74	D
LIST_S2	Uncertain	0.90	D;D;D;D;D
M_CAP	Benign	0.056	D
MetaRNN	Uncertain	0.73	D;D;D;D;D
MetaSVM	Benign	-0.54	T
MutationAssessor	Pathogenic	3.2	.;M;.;M;.
MutationTaster	Benign	0.88	D;D;D;D
PrimateAI	Benign	0.32	T
PROVEAN	Uncertain	-2.9	.;D;N;D;D
REVEL	Benign	0.24
Sift	Uncertain	0.014	.;D;D;D;D
Sift4G	Uncertain	0.0040	D;D;D;D;D
Polyphen		0.42, 0.68	.;B;P;.;.
Vest4		0.65
MutPred		0.49		.;Loss of disorder (P = 0.0133);.;Loss of disorder (P = 0.0133);Loss of disorder (P = 0.0133);
MVP		0.63
MPC		0.48
ClinPred		0.95	D
GERP RS		1.1
Varity_R		0.17
gMVP		0.61

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs765702033; hg19: chr6-75851852;