rs765702033

Variant names:

• chr6-75142136-C-A
• rs765702033
• NM_004370.6:c.4853G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_004370.6(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. 13/22 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 NM_004370.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.273
• Publications: 0 publications found

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]

COL12A1 Gene-Disease associations (from GenCC):

• Bethlem myopathy 2

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• Bethlem myopathy 2

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Illumina, Genomics England PanelApp
• Ullrich congenital muscular dystrophy 2

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• Bethlem myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Ullrich congenital muscular dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004370.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL12A1	NM_004370.6	MANE Select	c.4853G>T	p.Ser1618Ile	missense	Exon 27 of 66	NP_004361.3
	COL12A1	NM_001424113.1		c.4853G>T	p.Ser1618Ile	missense	Exon 27 of 66	NP_001411042.1
	COL12A1	NM_001424114.1		c.4853G>T	p.Ser1618Ile	missense	Exon 27 of 65	NP_001411043.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL12A1	ENST00000322507.13	TSL:1 MANE Select	c.4853G>T	p.Ser1618Ile	missense	Exon 27 of 66	ENSP00000325146.8
	COL12A1	ENST00000345356.10	TSL:1	c.1361G>T	p.Ser454Ile	missense	Exon 12 of 51	ENSP00000305147.9
	COL12A1	ENST00000483888.6	TSL:5	c.4853G>T	p.Ser1618Ile	missense	Exon 27 of 65	ENSP00000421216.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249410 AF XY: 0.00000739

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 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

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111962

Other (OTH) AF: 0.00 AC: 0 AN: 60394

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

Jan 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 v4.9

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
Eigen	Benign	0.045
Eigen_PC	Benign	-0.025
FATHMM_MKL	Benign	0.74	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.056	D
MetaRNN	Uncertain	0.73	D
MetaSVM	Benign	-0.54	T
MutationAssessor	Pathogenic	3.2	M
PhyloP100		0.27
PrimateAI	Benign	0.32	T
PROVEAN	Uncertain	-2.9	D
REVEL	Benign	0.24
Sift	Uncertain	0.014	D
Sift4G	Uncertain	0.0040	D
Polyphen		0.42	B
Vest4		0.65
MutPred		0.49		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
Mutation Taster		=61/39	polymorphism

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

Other links and lift over

dbSNP: rs765702033; hg19: chr6-75851852;