NM_001844.5:c.1999C>A

Variant names:

• chr12-47983435-G-T
• rs121912885
• NM_001844.5:c.1999C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 5P and 2B. PM1 PM5 PP2 BP4 BP6

The NM_001844.5(COL2A1):​c.1999C>A​(p.Leu667Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000753 in 1,461,778 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L667F) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: COL2A1 NM_001844.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 3.55
• Publications: 5 publications found

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]

COL2A1 Gene-Disease associations (from GenCC):

• achondrogenesis type II

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, ClinGen, G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• Kniest dysplasia

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, ClinGen, Labcorp Genetics (formerly Invitae)
• platyspondylic dysplasia, Torrance type

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• spondyloepimetaphyseal dysplasia, Strudwick type

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
• spondyloepiphyseal dysplasia congenita

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• spondyloepiphyseal dysplasia with metatarsal shortening

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: ClinGen, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• spondylometaphyseal dysplasia

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• spondyloperipheral dysplasia

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Stickler syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, ClinGen, Illumina, Orphanet, Genomics England PanelApp
• Stickler syndrome, type I, nonsyndromic ocular

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• avascular necrosis of femoral head, primary, 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• Legg-Calve-Perthes disease

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• mild spondyloepiphyseal dysplasia due to COL2A1 mutation with early-onset osteoarthritis

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• otospondylomegaepiphyseal dysplasia, autosomal recessive

  Inheritance: AD, AR Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• spondyloepiphyseal dysplasia, Stanescu type

  Inheritance: AD Classification: MODERATE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• autosomal dominant rhegmatogenous retinal detachment

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dysspondyloenchondromatosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial avascular necrosis of femoral head

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hypochondrogenesis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• multiple epiphyseal dysplasia, Beighton type

  Inheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• spondylometaphyseal dysplasia, Schmidt type

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• otospondylomegaepiphyseal dysplasia

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
• vitreoretinopathy with phalangeal epiphyseal dysplasia

  Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 4 uncertain in NM_001844.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-47983435-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 17384.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP2: Missense variant in the COL2A1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 376 curated pathogenic missense variants (we use a threshold of 10). The gene has 125 curated benign missense variants. Gene score misZ: 3.2926 (above the threshold of 3.09). Trascript score misZ: 5.3726 (above the threshold of 3.09). GenCC associations: The gene is linked to vitreoretinopathy with phalangeal epiphyseal dysplasia, Stickler syndrome, type I, nonsyndromic ocular, Kniest dysplasia, Stickler syndrome type 1, platyspondylic dysplasia, Torrance type, spondyloepiphyseal dysplasia with metatarsal shortening, spondyloperipheral dysplasia, spondyloepiphyseal dysplasia, Stanescu type, Legg-Calve-Perthes disease, achondrogenesis type II, spondyloepiphyseal dysplasia congenita, multiple epiphyseal dysplasia, Beighton type, mild spondyloepiphyseal dysplasia due to COL2A1 mutation with early-onset osteoarthritis, autosomal dominant rhegmatogenous retinal detachment, spondylometaphyseal dysplasia, spondyloepimetaphyseal dysplasia, Strudwick type, familial avascular necrosis of femoral head, dysspondyloenchondromatosis, spondylometaphyseal dysplasia, Schmidt type, hypochondrogenesis, otospondylomegaepiphyseal dysplasia, autosomal recessive, otospondylomegaepiphyseal dysplasia, avascular necrosis of femoral head, primary, 1.
• BP4: Computational evidence support a benign effect (MetaRNN=0.29503363).
• BP6: Variant 12-47983435-G-T is Benign according to our data. Variant chr12-47983435-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1899489.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001844.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL2A1	NM_001844.5	MANE Select	c.1999C>A	p.Leu667Ile	missense	Exon 31 of 54	NP_001835.3
	COL2A1	NM_033150.3		c.1792C>A	p.Leu598Ile	missense	Exon 30 of 53	NP_149162.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL2A1	ENST00000380518.8	TSL:1 MANE Select	c.1999C>A	p.Leu667Ile	missense	Exon 31 of 54	ENSP00000369889.3
	COL2A1	ENST00000337299.7	TSL:1	c.1792C>A	p.Leu598Ile	missense	Exon 30 of 53	ENSP00000338213.6
	COL2A1	ENST00000483376.1	TSL:5	n.177C>A		non_coding_transcript_exon	Exon 2 of 8

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 251022 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000218

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000753 AC: 11 AN: 1461778 Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3 AN XY: 727198

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.0000504 AC: 2 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86246

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53382

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000809 AC: 9 AN: 1111978

Other (OTH) AF: 0.00 AC: 0 AN: 60384

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Feb 17, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1999C>A (p.L667I) alteration is located in exon 31 (coding exon 31) of the COL2A1 gene. This alteration results from a C to A substitution at nucleotide position 1999, causing the leucine (L) at amino acid position 667 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

not provided Benign:1

Apr 24, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Benign	-0.034	T
BayesDel_noAF	Uncertain	0.010
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.37	T
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Benign	0.061	D
MetaRNN	Benign	0.30	T
MetaSVM	Uncertain	0.45	D
MutationAssessor	Benign	0.93	L
PhyloP100		3.5
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-1.3	N
REVEL	Uncertain	0.49
Sift	Benign	0.035	D
Sift4G	Benign	0.083	T
Polyphen		0.53	P
Vest4		0.51
MutPred		0.47		Loss of glycosylation at P668 (P = 0.1402)
MVP		0.69
MPC		1.3
ClinPred		0.38	T
GERP RS		4.9
Varity_R		0.32
gMVP		0.16
Mutation Taster		=43/57	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		2.0
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: rs121912885; hg19: chr12-48377218; COSMIC: COSV105220706;