7-94395089-G-A

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2 BP4_Moderate

The NM_000089.4(COL1A2):c.58G>A(p.Ala20Thr) variant causes a missense change. The variant allele was found at a frequency of 0.0000103 in 1,461,776 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A20A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: COL1A2 NM_000089.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.84

Genes affected

COL1A2 (HGNC:2198): (collagen type I alpha 2 chain) This gene encodes the pro-alpha2 chain of type I collagen whose triple helix comprises two alpha1 chains and one alpha2 chain. Type I is a fibril-forming collagen found in most connective tissues and is abundant in bone, cornea, dermis and tendon. Mutations in this gene are associated with osteogenesis imperfecta types I-IV, Ehlers-Danlos syndrome type VIIB, recessive Ehlers-Danlos syndrome Classical type, idiopathic osteoporosis, and atypical Marfan syndrome. Symptoms associated with mutations in this gene, however, tend to be less severe than mutations in the gene for the alpha1 chain of type I collagen (COL1A1) reflecting the different role of alpha2 chains in matrix integrity. Three transcripts, resulting from the use of alternate polyadenylation signals, have been identified for this gene. [provided by R. Dalgleish, Feb 2008]

(HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PP2: Missense variant where missense usually causes diseases, COL1A2
• BP4: Computational evidence support a benign effect (MetaRNN=0.16014224).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL1A2	NM_000089.4	c.58G>A	p.Ala20Thr	missense_variant	1/52	ENST00000297268.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL1A2	ENST00000297268.11	c.58G>A	p.Ala20Thr	missense_variant	1/52	1	NM_000089.4	P1
	ENST00000644739.1	n.69+451C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000318 AC: 8 AN: 251184 Hom.: 0 AF XY: 0.0000442 AC XY: 6 AN XY: 135770

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: 0.000261

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461776 Hom.: 0 Cov.: 30 AF XY: 0.0000165 AC XY: 12 AN XY: 727194

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: 0.000162

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Osteogenesis imperfecta type I;C0268335:Ehlers-Danlos syndrome, classic type, 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 23, 2023

This variant is present in population databases (rs777426777, gnomAD 0.03%). 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. 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 COL1A2 protein function. ClinVar contains an entry for this variant (Variation ID: 2183136). This variant has not been reported in the literature in individuals affected with COL1A2-related conditions. This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 20 of the COL1A2 protein (p.Ala20Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.23
Cadd	Benign	23
Dann	Uncertain	0.99
DEOGEN2	Benign	0.16	T;.
Eigen	Benign	-0.31
Eigen_PC	Benign	-0.23
FATHMM_MKL	Uncertain	0.78	D
LIST_S2	Benign	0.79	T;T
M_CAP	Benign	0.079	D
MetaRNN	Benign	0.16	T;T
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Uncertain	2.1	M;.
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.68	N;.
REVEL	Benign	0.28
Sift	Benign	0.087	T;.
Sift4G	Benign	0.41	T;T
Polyphen		0.0070	B;.
Vest4		0.13
MutPred		0.55		Loss of helix (P = 0.0167);Loss of helix (P = 0.0167);
MVP		0.60
MPC		0.25
ClinPred		0.12	T
GERP RS		2.4
Varity_R		0.069
gMVP		0.45

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: rs777426777; hg19: chr7-94024401;