8-138589432-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_152888.3(COL22A1):c.4702G>A(p.Gly1568Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000035 in 1,401,692 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000035 (0 hom.)
• Consequence: COL22A1 NM_152888.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.31

Genes affected

COL22A1 (HGNC:22989): (collagen type XXII alpha 1 chain) This gene encodes member of the collagen family which is thought to contribute to the stabilization of myotendinous junctions and strengthen skeletal muscle attachments during contractile activity. It belongs to the fibril-associated collagens with interrupted triple helix (FACIT) subset of the collagen superfamily, which associate with collagen fibers through their C-terminal collagenous domains and mediate protein-protein interactions through their N-terminal noncollagenous domains. The encoded protein is deposited in the basement membrane zone of the myotendinous junction which is present only at the tissue junctions of muscles, tendons, the heart, articular cartilage, and skin. A knockdown of the orthologous zebrafish gene induces a muscular dystrophy by disruption of the myotendinous junction. [provided by RefSeq, May 2017]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.954

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL22A1	NM_152888.3	c.4702G>A	p.Gly1568Arg	missense_variant	65/65	ENST00000303045.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL22A1	ENST00000303045.11	c.4702G>A	p.Gly1568Arg	missense_variant	65/65	1	NM_152888.3	P1
COL22A1	ENST00000341807.8	n.2387G>A		non_coding_transcript_exon_variant	39/39	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000350 AC: 49 AN: 1401692 Hom.: 0 Cov.: 31 AF XY: 0.0000361 AC XY: 25 AN XY: 693050

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: 0.0000254

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000397

Gnomad4 OTH exome AF: 0.0000695

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000342 Hom.: 0

Bravo AF: 0.00000378

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 05, 2023

The c.4702G>A (p.G1568R) alteration is located in exon 65 (coding exon 64) of the COL22A1 gene. This alteration results from a G to A substitution at nucleotide position 4702, causing the glycine (G) at amino acid position 1568 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
Cadd	Pathogenic	28
Dann	Uncertain	1.0
DEOGEN2	Benign	0.067	T;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.95	D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.0	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-5.9	D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.89
MutPred		0.88		Gain of methylation at G1568 (P = 0.0228);.;
MVP		0.69
MPC		0.10
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.81
gMVP		0.79

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs368533920; hg19: chr8-139601675;