chr2-237376870-G-A

Position:

chr2-237376870-G-A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2BP4_StrongBP6

The NM_004369.4(COL6A3):c.2972C>T(p.Ala991Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000133 in 1,614,068 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00014 ( 1 hom. )

Consequence

COL6A3
NM_004369.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:2

Conservation

PhyloP100: 0.591

Variant links:

Genes affected

COL6A3 (HGNC:2213): (collagen type VI alpha 3 chain) This gene encodes the alpha-3 chain, one of the three alpha chains of type VI collagen, a beaded filament collagen found in most connective tissues. The alpha-3 chain of type VI collagen is much larger than the alpha-1 and -2 chains. This difference in size is largely due to an increase in the number of subdomains, similar to von Willebrand Factor type A domains, that are found in the amino terminal globular domain of all the alpha chains. These domains have been shown to bind extracellular matrix proteins, an interaction that explains the importance of this collagen in organizing matrix components. Mutations in the type VI collagen genes are associated with Bethlem myopathy, a rare autosomal dominant proximal myopathy with early childhood onset. Mutations in this gene are also a cause of Ullrich congenital muscular dystrophy, also referred to as Ullrich scleroatonic muscular dystrophy, an autosomal recessive congenital myopathy that is more severe than Bethlem myopathy. Multiple transcript variants have been identified, but the full-length nature of only some of these variants has been described. [provided by RefSeq, Jun 2009]

COL6A3 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.042110503).

BP6

Variant 2-237376870-G-A is Benign according to our data. Variant chr2-237376870-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 476515.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL6A3	NM_004369.4 linkuse as main transcript	c.2972C>T	p.Ala991Val	missense_variant	7/44	ENST00000295550.9	NP_004360.2	P12111-1D9ZGF2Q8N4Z1Q63HQ4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL6A3	ENST00000295550.9 linkuse as main transcript	c.2972C>T	p.Ala991Val	missense_variant	7/44	1	NM_004369.4	ENSP00000295550.4		P12111-1

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000159

AC:

AN:

251494

Hom.:

AF XY:

0.000191

AC XY:

AN XY:

135920

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.000784

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000114

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000142

AC:

207

AN:

1461894

Hom.:

Cov.:

AF XY:

0.000184

AC XY:

134

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.000835

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000102

Gnomad4 OTH exome

AF:

0.000199

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74340

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000882

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000844

Hom.:

Bravo

AF:

0.0000869

ExAC

AF:

0.000173

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 02, 2021

The c.2972C>T (p.A991V) alteration is located in exon 7 (coding exon 6) of the COL6A3 gene. This alteration results from a C to T substitution at nucleotide position 2972, causing the alanine (A) at amino acid position 991 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Tip-toe gait

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino

Nov 25, 2020

We conducted a clinical examination of patients about toe walking. The COL6A3:c.2972C>T was detected in 1 patient. This variant has not yet been reported in the HGMD and LOVD databases or in the literature. However, it is classified in the ClinVar database as likely benigne in relation to Bethlem myopathy (1 entry). Different in-silico prediction programs [MutationTaster, PolyPhen-2, MutationAssessor] do not assign functional significance to the variant. Influence on altered splicing of mRNA could also not be determined [MutationTaster, varSEAK]. Based on the available data, this variant is classified as VUS. Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -

Bethlem myopathy 1A

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 12, 2024

- -

not provided

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Revvity Omics, Revvity

Mar 21, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.42

CADD

Benign

DANN

Uncertain

0.97

DEOGEN2

Benign

0.24

.;T;.;T;.;.;.

Eigen

Benign

-0.74

Eigen_PC

Benign

-0.79

FATHMM_MKL

Benign

0.19

LIST_S2

Benign

0.83

T;T;T;T;.;T;T

M_CAP

Benign

0.0078

MetaRNN

Benign

0.042

T;T;T;T;T;T;T

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.69

.;N;.;.;.;.;.

PrimateAI

Benign

0.35

PROVEAN

Benign

-1.6

N;N;N;.;N;N;N

REVEL

Benign

0.095

Sift

Benign

0.14

T;T;T;.;T;T;T

Sift4G

Benign

0.19

T;T;T;T;T;T;T

Polyphen

0.53

P;B;.;.;P;.;.

Vest4

0.079

MutPred

0.50

.;Gain of helix (P = 0.0696);.;.;.;.;.;

MVP

0.42

MPC

0.18

ClinPred

0.014

GERP RS

1.3

Varity_R

0.033

gMVP

0.58

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

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