rs868695034

Positions:

• chr2-189051417-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP2 PP3_Strong

The NM_000393.5(COL5A2):​c.2834G>A​(p.Gly945Glu) variant causes a missense change involving the alteration of a 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G945R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL5A2 NM_000393.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.90

Genes affected

COL5A2 (HGNC:2210): (collagen type V alpha 2 chain) This gene encodes an alpha chain for one of the low abundance fibrillar collagens. Fibrillar collagen molecules are trimers that can be composed of one or more types of alpha chains. Type V collagen is found in tissues containing type I collagen and appears to regulate the assembly of heterotypic fibers composed of both type I and type V collagen. This gene product is closely related to type XI collagen and it is possible that the collagen chains of types V and XI constitute a single collagen type with tissue-specific chain combinations. Mutations in this gene are associated with Ehlers-Danlos syndrome, types I and II. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-189051418-C-T is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), COL5A2. . Gene score misZ 2.4395 (greater than the threshold 3.09). Trascript score misZ 3.3523 (greater than threshold 3.09). GenCC has associacion of gene with Ehlers-Danlos syndrome, classic type, 2, Ehlers-Danlos syndrome, classic type.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL5A2	NM_000393.5	c.2834G>A	p.Gly945Glu	missense_variant	42/54	ENST00000374866.9	NP_000384.2
COL5A2	XM_011510573.4	c.2696G>A	p.Gly899Glu	missense_variant	45/57		XP_011508875.1
COL5A2	XM_047443251.1	c.2696G>A	p.Gly899Glu	missense_variant	47/59		XP_047299207.1
COL5A2	XM_047443252.1	c.2696G>A	p.Gly899Glu	missense_variant	46/58		XP_047299208.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL5A2	ENST00000374866.9	c.2834G>A	p.Gly945Glu	missense_variant	42/54	1	NM_000393.5	ENSP00000364000.3
COL5A2	ENST00000618828.1	c.1673G>A	p.Gly558Glu	missense_variant	35/47	5		ENSP00000482184.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00213 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Ehlers-Danlos syndrome, classic type, 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 11, 2017

In summary, this variant is a novel missense change affecting a residue that is critical for protein structure, stability and function. However, the available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236), and missense variants at these glycine residues in COL5A2 are more frequently observed in individuals with disease than in the general population (PMID: 22696272, 23587214). However, the clinical significance of this observation remains uncertain since only a limited number of affected individuals have been described to date. 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 disruptive, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a COL5A2-related disease. This sequence change replaces glycine with glutamic acid at codon 945 of the COL5A2 protein (p.Gly945Glu). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and glutamic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D;T;D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Pathogenic	0.98	.;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.3	H;.;H
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-7.1	D;.;.
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;.;.
Sift4G	Pathogenic	0.0010	D;D;.
Polyphen		1.0	D;.;D
Vest4		0.98
MutPred		1.0		Loss of methylation at R944 (P = 0.0332);.;Loss of methylation at R944 (P = 0.0332);
MVP		0.99
MPC		0.33
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.73
gMVP		0.99

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: rs868695034; hg19: chr2-189916143;