chr6-75175202-G-T

Position:

• chr6-75175202-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_004370.6(COL12A1):​c.2546C>A​(p.Thr849Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 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: 0.0000014 (0 hom.)
• Consequence: COL12A1 NM_004370.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.94

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 1 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.12862074).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL12A1	NM_004370.6	c.2546C>A	p.Thr849Asn	missense_variant	13/66	ENST00000322507.13	NP_004361.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL12A1	ENST00000322507.13	c.2546C>A	p.Thr849Asn	missense_variant	13/66	1	NM_004370.6	ENSP00000325146.8
COL12A1	ENST00000345356.10	c.74-22720C>A		intron_variant		1		ENSP00000305147.9
COL12A1	ENST00000483888.6	c.2546C>A	p.Thr849Asn	missense_variant	13/65	5		ENSP00000421216.1
COL12A1	ENST00000416123.6	c.2546C>A	p.Thr849Asn	missense_variant	12/63	5		ENSP00000412864.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000401 AC: 1 AN: 249486 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135364

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: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461892 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727246

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

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

Oct 23, 2017

This sequence change replaces threonine with asparagine at codon 849 of the COL12A1 protein (p.Thr849Asn). The threonine residue is moderately conserved and there is a small physicochemical difference between threonine and asparagine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with COL12A1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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	0.11
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.52
CADD	Benign	20
DANN	Benign	0.97
DEOGEN2	Benign	0.076	T;.;.
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.10
FATHMM_MKL	Benign	0.73	D
LIST_S2	Benign	0.74	T;T;T
M_CAP	Benign	0.0093	T
MetaRNN	Benign	0.13	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.9	L;L;.
PrimateAI	Benign	0.39	T
PROVEAN	Benign	-0.15	N;N;N
REVEL	Benign	0.037
Sift	Benign	0.28	T;T;T
Sift4G	Benign	0.23	T;T;T
Polyphen		0.0030	B;.;.
Vest4		0.17
MutPred		0.39		Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);Loss of sheet (P = 0.0457);
MVP		0.32
MPC		0.14
ClinPred		0.074	T
GERP RS		4.0
Varity_R		0.024
gMVP		0.60

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: rs559028883; hg19: chr6-75884918;