NM_207122.2:c.544C>T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_207122.2(EXT2):c.544C>T(p.Arg182*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000248 in 1,613,850 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 (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

EXT2
NM_207122.2 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 4.00

Publications

12 publications found

Variant links:

Genes affected

EXT2 (HGNC:3513): (exostosin glycosyltransferase 2) This gene encodes one of two glycosyltransferases involved in the chain elongation step of heparan sulfate biosynthesis. Mutations in this gene cause the type II form of multiple exostoses. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene. [provided by RefSeq, Jul 2008]

EXT2 Gene-Disease associations (from GenCC):

exostoses, multiple, type 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics, G2P
seizures-scoliosis-macrocephaly syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet
hereditary multiple osteochondromas
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

EXT2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 11-44109201-C-T is Pathogenic according to our data. Variant chr11-44109201-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 265133.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
EXT2	NM_207122.2 link	c.544C>T	p.Arg182*	stop_gained	Exon 3 of 14	ENST00000533608.7	NP_997005.1	Q93063-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
EXT2	ENST00000533608.7 link	c.544C>T	p.Arg182*	stop_gained	Exon 3 of 14	1	NM_207122.2	ENSP00000431173.2		Q93063-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152114

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000208

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461736

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727184

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111896

Other (OTH)

AF:

0.0000166

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.408

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152114

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74308

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41424

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.000208

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2084

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Exostoses, multiple, type 2

Pathogenic:3

Jun 19, 2023

Institute of Human Genetics, Heidelberg University

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Neuberg Centre For Genomic Medicine, NCGM

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The stop gained c.544C>T (p.Arg182Ter) variant has been observed in individuals and families affected with hereditary multiple osteochondromatosis (DobsonStone C et al). The p.Arg182Ter variant is novel (not in any individuals) in gnomAD Exomes and is novel (not in any individuals) in 1000 Genomes. This variant has been submitted to the ClinVar database as Pathogenic. The nucleotide change c.544C>T in EXT2 is predicted as conserved by GERP++ and PhyloP across 100 vertebrates. This variant is predicted to cause loss of normal protein function through protein truncation. Loss of function variants have been previously reported to be disease causing. For these reasons, this variant has been classified as Pathogenic. -

Nov 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg182*) in the EXT2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in EXT2 are known to be pathogenic (PMID: 10679937, 19810120). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with hereditary multiple osteochondromatosis (PMID: 10713884, 23262345, 23439489, 23629877, 26961984). Invitae Evidence Modeling of clinical and family history, age, sex, and reported ancestry of multiple individuals with this EXT2 variant has been performed. This variant is expected to be pathogenic with a positive predictive value of at least 99%. This is a validated machine learning model that incorporates the clinical features of 50,122 individuals referred to our laboratory for EXT2 testing. ClinVar contains an entry for this variant (Variation ID: 265133). For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:2

Oct 24, 2023

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 27616605, 30334991, 25525159, 23439489, 10713884, 26961984, 30105120, 23629877, 23262345, 33632255, 32293802, 33414810) -

Mar 01, 2019

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Exostoses, multiple, type 2;C4225248:Seizures-scoliosis-macrocephaly syndrome

Pathogenic:1

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

PVS1+PM2_Supporting+PS4_Supporting+PP1+PP4 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.63

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.75

Eigen_PC

Uncertain

0.61

FATHMM_MKL

Uncertain

0.94

PhyloP100

4.0

Vest4

0.89

GERP RS

4.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over