21-45981851-A-T

Variant names:

• chr21-45981851-A-T
• NM_001848.3:c.1A>T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001848.3(COL6A1):​c.1A>T​(p.Met1?) variant causes a initiator codon change involving the alteration of a non-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 (★).

• Frequency: Genomes: not found (cov: 29)
• Consequence: COL6A1 NM_001848.3 initiator_codon
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.580

Genes affected

COL6A1 (HGNC:2211): (collagen type VI alpha 1 chain) The collagens are a superfamily of proteins that play a role in maintaining the integrity of various tissues. Collagens are extracellular matrix proteins and have a triple-helical domain as their common structural element. Collagen VI is a major structural component of microfibrils. The basic structural unit of collagen VI is a heterotrimer of the alpha1(VI), alpha2(VI), and alpha3(VI) chains. The alpha2(VI) and alpha3(VI) chains are encoded by the COL6A2 and COL6A3 genes, respectively. The protein encoded by this gene is the alpha 1 subunit of type VI collagen (alpha1(VI) chain). Mutations in the genes that code for the collagen VI subunits result in the autosomal dominant disorder, Bethlem myopathy. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 3 pathogenic variants. Next in-frame start position is after 106 codons. Genomic position: 45984357. Lost 0.102 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A1	NM_001848.3	c.1A>T	p.Met1?	initiator_codon_variant	Exon 1 of 35	ENST00000361866.8	NP_001839.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A1	ENST00000361866.8	c.1A>T	p.Met1?	initiator_codon_variant	Exon 1 of 35	1	NM_001848.3	ENSP00000355180.3

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 29

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Uncertain:1

Jul 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. ClinVar contains an entry for this variant (Variation ID: 1522832). Disruption of the initiator codon has been observed in individual(s) with clinical features of autosomal recessive COL6A1-related conditions (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects the initiator methionine of the COL6A1 mRNA. The next in-frame methionine is located at codon 106. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Benign	20
DANN	Benign	0.73
DEOGEN2	Benign	0.22	T;T
Eigen	Benign	-0.49
Eigen_PC	Benign	-0.52
FATHMM_MKL	Benign	0.14	N
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.79	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	-0.12	T
PROVEAN	Benign	-0.76	N;.
REVEL	Uncertain	0.51
Sift	Pathogenic	0.0	D;.
Sift4G	Benign	0.24	T;T
Polyphen		0.23	B;.
Vest4		0.74
MutPred		0.97		Loss of MoRF binding (P = 0.0705);Loss of MoRF binding (P = 0.0705);
MVP		0.97
ClinPred		0.96	D
GERP RS		2.8
Varity_R		0.90
gMVP		0.26

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr21-47401765;