chr21-45992830-G-A

Variant names:

• chr21-45992830-G-A
• rs9306146
• NM_001848.3:c.1335+20G>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001848.3(COL6A1):​c.1335+20G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000699 in 1,430,186 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: COL6A1 NM_001848.3 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0830
• Publications: 0 publications found

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]

COL6A1 Gene-Disease associations (from GenCC):

• collagen 6-related myopathy

  Inheritance: AD, AR Classification: DEFINITIVE Submitted by: ClinGen
• Bethlem myopathy 1A

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P
• Ullrich congenital muscular dystrophy 1A

  Inheritance: AD, AR Classification: STRONG Submitted by: Genomics England PanelApp, 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: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A1	NM_001848.3	c.1335+20G>A		intron_variant	Intron 19 of 34	ENST00000361866.8	NP_001839.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A1	ENST00000361866.8	c.1335+20G>A		intron_variant	Intron 19 of 34	1	NM_001848.3	ENSP00000355180.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 6.99e-7 AC: 1 AN: 1430186 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 708322

African (AFR) AF: 0.00 AC: 0 AN: 33094

American (AMR) AF: 0.00 AC: 0 AN: 40096

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25434

East Asian (EAS) AF: 0.00 AC: 0 AN: 38628

South Asian (SAS) AF: 0.0000122 AC: 1 AN: 81848

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50238

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5634

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1095954

Other (OTH) AF: 0.00 AC: 0 AN: 59260

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	1.6
DANN	Benign	0.78
PhyloP100		-0.083

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

Other links and lift over

dbSNP: rs9306146; hg19: chr21-47412744;