rs12721427

Positions:

• chr12-47974758-C-G
• chr12-47974758-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 5P and 2B. PM1 PM2 PP2 BP4_Moderate

The NM_001844.5(COL2A1):​c.3991G>C​(p.Val1331Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V1331I) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: COL2A1 NM_001844.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.08

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 Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 6 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.1937685).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL2A1	NM_001844.5	c.3991G>C	p.Val1331Leu	missense_variant	52/54	ENST00000380518.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL2A1	ENST00000380518.8	c.3991G>C	p.Val1331Leu	missense_variant	52/54	1	NM_001844.5	P1
COL2A1	ENST00000337299.7	c.3784G>C	p.Val1262Leu	missense_variant	51/53	1
COL2A1	ENST00000493991.5	n.3077G>C		non_coding_transcript_exon_variant	35/37	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461894 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Benign	-0.071	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	21
DANN	Benign	0.95
DEOGEN2	Benign	0.37	T;.
Eigen	Benign	-0.30
Eigen_PC	Benign	-0.26
FATHMM_MKL	Uncertain	0.76	D
LIST_S2	Uncertain	0.87	D;D
M_CAP	Benign	0.041	D
MetaRNN	Benign	0.19	T;T
MetaSVM	Benign	-0.72	T
MutationAssessor	Benign	1.4	L;.
MutationTaster	Benign	0.99	N;N
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-1.5	N;N
REVEL	Benign	0.17
Sift	Benign	0.061	T;T
Sift4G	Benign	0.085	T;T
Polyphen		0.014	B;B
Vest4		0.31
MutPred		0.49		Loss of methylation at K1333 (P = 0.0761);.;
MVP		0.48
MPC		0.31
ClinPred		0.74	D
GERP RS		4.9
Varity_R		0.16
gMVP		0.59

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: rs12721427; hg19: chr12-48368541;