12-47987735-TGAA-TGAAGAAGAA

Variant names:

• chr12-47987735-T-TGAAGAA
• rs760530147
• NM_001844.5:c.1123-32_1123-27dupTTCTTC

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001844.5(COL2A1):​c.1123-32_1123-27dupTTCTTC variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000702 in 1,425,468 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. There are indicators that this mutation may affect the branch point..

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: COL2A1 NM_001844.5 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.258
• Publications: 0 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 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
COL2A1	NM_001844.5	c.1123-32_1123-27dupTTCTTC		intron_variant	Intron 18 of 53	ENST00000380518.8	NP_001835.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL2A1	ENST00000380518.8	c.1123-27_1123-26insTTCTTC		intron_variant	Intron 18 of 53	1	NM_001844.5	ENSP00000369889.3
COL2A1	ENST00000337299.7	c.916-27_916-26insTTCTTC		intron_variant	Intron 17 of 52	1		ENSP00000338213.6
COL2A1	ENST00000493991.5	n.47-27_47-26insTTCTTC		intron_variant	Intron 1 of 36	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.02e-7 AC: 1 AN: 1425468 Hom.: 0 Cov.: 27 AF XY: 0.00000141 AC XY: 1 AN XY: 708518

African (AFR) AF: 0.00 AC: 0 AN: 32594

American (AMR) AF: 0.0000232 AC: 1 AN: 43194

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25632

East Asian (EAS) AF: 0.00 AC: 0 AN: 38692

South Asian (SAS) AF: 0.00 AC: 0 AN: 83432

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52050

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5734

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1085180

Other (OTH) AF: 0.00 AC: 0 AN: 58960

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.26
La Branchor		0.88
BranchPoint Hunter		3.0

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs760530147; hg19: chr12-48381518;