rs119103290

Variant names:

• chr8-117837146-G-A
• rs119103290
• NM_000127.3:c.1018C>T

Your query was ambiguous. Multiple possible variants found:

• chr8-117837146-G-A
• chr8-117837146-G-C

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000127.3(EXT1):​c.1018C>T​(p.Arg340Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,746 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R340G) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: EXT1 NM_000127.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8
• Conservation: PhyloP100: 6.71
• Publications: 11 publications found

Genes affected

EXT1 (HGNC:3512): (exostosin glycosyltransferase 1) This gene encodes an endoplasmic reticulum-resident type II transmembrane glycosyltransferase involved in the chain elongation step of heparan sulfate biosynthesis. Mutations in this gene cause the type I form of multiple exostoses. [provided by RefSeq, Jul 2008]

EXT1 Gene-Disease associations (from GenCC):

• exostoses, multiple, type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen
• chondrosarcoma

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• hereditary multiple osteochondromas

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PM1: In a hotspot region, there are 15 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000127.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-117837146-G-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 988576.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.968
• PP5: Variant 8-117837146-G-A is Pathogenic according to our data. Variant chr8-117837146-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 2500.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000127.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	EXT1	NM_000127.3	MANE Select	c.1018C>T	p.Arg340Cys	missense	Exon 2 of 11	NP_000118.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	EXT1	ENST00000378204.7	TSL:1 MANE Select	c.1018C>T	p.Arg340Cys	missense	Exon 2 of 11	ENSP00000367446.3	Q16394
	EXT1	ENST00000436216.2	TSL:3	n.385C>T		non_coding_transcript_exon	Exon 2 of 6	ENSP00000400372.1	H7C1H6
	EXT1	ENST00000684189.1		n.485C>T		non_coding_transcript_exon	Exon 2 of 11

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461746 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727186

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86230

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111930

Other (OTH) AF: 0.0000166 AC: 1 AN: 60392

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000723 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	Exostoses, multiple, type 1 (2)
2	-	-	not provided (2)
1	-	-	Chondrosarcoma;CN263289:Exostoses, multiple, type 1 (1)
1	-	-	EXT1-related disorder (1)
1	-	-	Inborn genetic diseases (1)
1	-	-	Multiple congenital exostosis (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Uncertain	0.63
Eigen_PC	Pathogenic	0.66
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.97	D
M_CAP	Pathogenic	0.37	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	0.43	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		6.7
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		0.99	D
Vest4		0.84
MutPred		0.85		Loss of methylation at R340 (P = 0.0346)
MVP		0.99
MPC		1.4
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.67
gMVP		0.90
Mutation Taster		=11/89	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs119103290; hg19: chr8-118849385; COSMIC: COSV108236790;