rs121912885

Positions:

• chr12-47983435-G-A
• chr12-47983435-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_001844.5(COL2A1):​c.1999C>T​(p.Leu667Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,778 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 Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L667I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL2A1 NM_001844.5 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1 O:1
• Conservation: PhyloP100: 3.55

Genes affected

COL2A1 (HGNC:2200): (collagen type II alpha 1 chain) This gene encodes the alpha-1 chain of type II collagen, a fibrillar collagen found in cartilage and the vitreous humor of the eye. Mutations in this gene are associated with achondrogenesis, chondrodysplasia, early onset familial osteoarthritis, SED congenita, Langer-Saldino achondrogenesis, Kniest dysplasia, Stickler syndrome type I, and spondyloepimetaphyseal dysplasia Strudwick type. In addition, defects in processing chondrocalcin, a calcium binding protein that is the C-propeptide of this collagen molecule, are also associated with chondrodysplasia. There are two transcripts identified for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 uncertain in NM_001844.5
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), COL2A1. . Gene score misZ 3.2926 (greater than the threshold 3.09). Trascript score misZ 5.3726 (greater than threshold 3.09). GenCC has associacion of gene with spondylometaphyseal dysplasia, Schmidt type, spondyloepiphyseal dysplasia congenita, hypochondrogenesis, autosomal dominant rhegmatogenous retinal detachment, spondyloperipheral dysplasia, Kniest dysplasia, familial avascular necrosis of femoral head, spondylometaphyseal dysplasia, mild spondyloepiphyseal dysplasia due to COL2A1 mutation with early-onset osteoarthritis, otospondylomegaepiphyseal dysplasia, autosomal recessive, multiple epiphyseal dysplasia, Beighton type, otospondylomegaepiphyseal dysplasia, Legg-Calve-Perthes disease, achondrogenesis type II, spondyloepiphyseal dysplasia, Stanescu type, platyspondylic dysplasia, Torrance type, Stickler syndrome type 1, dysspondyloenchondromatosis, vitreoretinopathy with phalangeal epiphyseal dysplasia, Stickler syndrome, type I, nonsyndromic ocular, avascular necrosis of femoral head, primary, 1, spondyloepiphyseal dysplasia with metatarsal shortening, spondyloepimetaphyseal dysplasia, Strudwick type.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.858
• PP5: Variant 12-47983435-G-A is Pathogenic according to our data. Variant chr12-47983435-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 17384.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr12-47983435-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL2A1	NM_001844.5	c.1999C>T	p.Leu667Phe	missense_variant	31/54	ENST00000380518.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL2A1	ENST00000380518.8	c.1999C>T	p.Leu667Phe	missense_variant	31/54	1	NM_001844.5	P1
COL2A1	ENST00000337299.7	c.1792C>T	p.Leu598Phe	missense_variant	30/53	1
COL2A1	ENST00000483376.1	n.177C>T		non_coding_transcript_exon_variant	2/8	5
COL2A1	ENST00000493991.5	n.923C>T		non_coding_transcript_exon_variant	14/37	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461778 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727198

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: no assertion criteria provided

Submissions by phenotype

Stickler syndrome, type I, nonsyndromic ocular Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Feb 01, 2005

- -

Stickler syndrome type 1 Other:1

not provided, no classification provided

literature only

GeneReviews

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D;.
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.83	T;T
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.86	D;D
MetaSVM	Uncertain	0.74	D
MutationAssessor	Benign	1.0	L;.
MutationTaster	Benign	1.0	A;A
PrimateAI	Uncertain	0.64	T
PROVEAN	Uncertain	-2.9	D;D
REVEL	Pathogenic	0.82
Sift	Benign	0.043	D;D
Sift4G	Benign	0.11	T;T
Polyphen		0.92	P;P
Vest4		0.56
MutPred		0.79		Gain of glycosylation at P670 (P = 0.2664);.;
MVP		0.93
MPC		1.5
ClinPred		0.97	D
GERP RS		4.9
Varity_R		0.46
gMVP		0.37

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: rs121912885; hg19: chr12-48377218;