rs1188543260

Positions:

• chr6-75156473-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PP2 PP3

The ENST00000322507.13(COL12A1):​c.3034A>G​(p.Met1012Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000411 in 1,461,536 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1012T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: COL12A1 ENST00000322507.13 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.76

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 2 ACMG points.

• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.786

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL12A1	NM_004370.6	c.3034A>G	p.Met1012Val	missense_variant	15/66	ENST00000322507.13	NP_004361.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL12A1	ENST00000322507.13	c.3034A>G	p.Met1012Val	missense_variant	15/66	1	NM_004370.6	ENSP00000325146	P4
COL12A1	ENST00000345356.10	c.74-3991A>G		intron_variant		1		ENSP00000305147
COL12A1	ENST00000483888.6	c.3034A>G	p.Met1012Val	missense_variant	15/65	5		ENSP00000421216	A1
COL12A1	ENST00000416123.6	c.3034A>G	p.Met1012Val	missense_variant	14/63	5		ENSP00000412864

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461536 Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3 AN XY: 727070

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000378

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

Feb 12, 2018

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with COL12A1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces methionine with valine at codon 1012 of the COL12A1 protein (p.Met1012Val). The methionine residue is moderately conserved and there is a small physicochemical difference between methionine and valine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.27
BayesDel_addAF	Benign	0.00034	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Benign	0.085	T;.;.
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Benign	0.038	D
MetaRNN	Pathogenic	0.79	D;D;D
MetaSVM	Benign	-0.98	T
MutationAssessor	Benign	1.4	L;L;.
MutationTaster	Benign	0.99	D;D;D;D
PrimateAI	Benign	0.46	T
PROVEAN	Benign	-1.3	N;N;N
REVEL	Benign	0.24
Sift	Benign	0.13	T;T;T
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		0.99	D;.;.
Vest4		0.78
MutPred		0.66		Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);
MVP		0.46
MPC		0.19
ClinPred		0.87	D
GERP RS		2.9
Varity_R		0.15
gMVP		0.62

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: rs1188543260; hg19: chr6-75866189;