NM_001851.6:c.2684C>T

Variant names:

• chr6-70216979-G-A
• rs758916884
• NM_001851.6:c.2684C>T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001851.6(COL9A1):​c.2684C>T​(p.Pro895Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: COL9A1 NM_001851.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.39

Genes affected

COL9A1 (HGNC:2217): (collagen type IX alpha 1 chain) This gene encodes one of the three alpha chains of type IX collagen, which is a minor (5-20%) collagen component of hyaline cartilage. Type IX collagen is usually found in tissues containing type II collagen, a fibrillar collagen. Studies in knockout mice have shown that synthesis of the alpha 1 chain is essential for assembly of type IX collagen molecules, a heterotrimeric molecule, and that lack of type IX collagen is associated with early onset osteoarthritis. Mutations in this gene are associated with osteoarthritis in humans, with multiple epiphyseal dysplasia, 6, a form of chondrodysplasia, and with Stickler syndrome, a disease characterized by ophthalmic, orofacial, articular, and auditory defects. Two transcript variants that encode different isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL9A1	NM_001851.6	c.2684C>T	p.Pro895Leu	missense_variant	Exon 38 of 38	ENST00000357250.11	NP_001842.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL9A1	ENST00000357250.11	c.2684C>T	p.Pro895Leu	missense_variant	Exon 38 of 38	1	NM_001851.6	ENSP00000349790.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727226

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Apr 20, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The P895L variant has not beenpublished as pathogenic or been reported as benign to our knowledge. It is not observed in large population cohorts(Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The P895L variant is asemi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ insome properties. Furthermore, although this substitution occurs at a position that is not conserved across species, insilico analysis predicts this variant is probably damaging to the protein structure/function. Nonetheless, this variantlacks observation in a significant number of affected individuals, segregation data, and functional evidence, all ofwhich would further clarify pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.087
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.010
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.51	D;.
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	D;T
M_CAP	Uncertain	0.18	D
MetaRNN	Uncertain	0.55	D;D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Uncertain	2.7	M;.
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-3.4	D;D
REVEL	Uncertain	0.51
Sift	Benign	0.14	T;D
Sift4G	Benign	0.29	T;T
Polyphen		0.95	P;P
Vest4		0.36
MutPred		0.39		Loss of glycosylation at P895 (P = 0.0072);.;
MVP		0.98
MPC		0.33
ClinPred		0.96	D
GERP RS		5.9
Varity_R		0.12
gMVP		0.44

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: rs758916884; hg19: chr6-70926682;