11-44107687-G-T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_207122.2(EXT2):​c.-26G>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,608,230 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 Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000010 ( 0 hom. )

Consequence

EXT2
NM_207122.2 5_prime_UTR_premature_start_codon_gain

Scores

2
2
12

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 1.87

Publications

2 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

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.121367395).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
EXT2NM_207122.2 linkc.-26G>T 5_prime_UTR_premature_start_codon_gain_variant Exon 2 of 14 ENST00000533608.7 NP_997005.1 Q93063-1
EXT2NM_207122.2 linkc.-26G>T 5_prime_UTR_variant Exon 2 of 14 ENST00000533608.7 NP_997005.1 Q93063-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
EXT2ENST00000533608.7 linkc.-26G>T 5_prime_UTR_premature_start_codon_gain_variant Exon 2 of 14 1 NM_207122.2 ENSP00000431173.2 Q93063-1
EXT2ENST00000533608.7 linkc.-26G>T 5_prime_UTR_variant Exon 2 of 14 1 NM_207122.2 ENSP00000431173.2 Q93063-1

Frequencies

GnomAD3 genomes
AF:
0.0000197
AC:
3
AN:
152226
Hom.:
0
Cov.:
32
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:
0.000577
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000798
AC:
2
AN:
250474
AF XY:
0.0000148
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000290
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000103
AC:
15
AN:
1456004
Hom.:
0
Cov.:
32
AF XY:
0.00000830
AC XY:
6
AN XY:
722942
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33366
American (AMR)
AF:
0.0000224
AC:
1
AN:
44618
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26054
East Asian (EAS)
AF:
0.0000506
AC:
2
AN:
39540
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86064
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53304
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5750
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1107170
Other (OTH)
AF:
0.000183
AC:
11
AN:
60138
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.482
Heterozygous variant carriers
0
1
2
4
5
6
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000197
AC:
3
AN:
152226
Hom.:
0
Cov.:
32
AF XY:
0.0000269
AC XY:
2
AN XY:
74358
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41462
American (AMR)
AF:
0.00
AC:
0
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.000577
AC:
3
AN:
5202
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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.:
0
Bravo
AF:
0.0000151
ExAC
AF:
0.00000824
AC:
1
Asia WGS
AF:
0.000577
AC:
2
AN:
3478

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Exostoses, multiple, type 2 Uncertain:2
Jan 12, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Jun 17, 2025
St. Jude Molecular Pathology, St. Jude Children's Research Hospital
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The EXT2 c.74G>T p.(Cys25Phe) missense change has a maximum subpopulation frequency of 0.01% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org). The in silico tool REVEL predicts a benign effect on protein function, but to our knowledge this prediction has not been confirmed by functional studies. To our knowledge, this variant has not been reported in individuals with hereditary multiple exostoses. In summary, the evidence currently available is insufficient to determine the clinical significance of this variant. It has therefore been classified as of uncertain significance. -

EXT2-related disorder Uncertain:1
Jul 23, 2024
PreventionGenetics, part of Exact Sciences
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

The EXT2 c.74G>T variant is predicted to result in the amino acid substitution p.Cys25Phe. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.010% of alleles in individuals of East Asian descent in gnomAD and is interpreted as uncertain in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/304570/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Benign
-0.074
T
BayesDel_noAF
Benign
-0.17
CADD
Benign
18
DANN
Uncertain
0.99
Eigen
Benign
-0.18
Eigen_PC
Benign
0.012
FATHMM_MKL
Benign
0.46
N
LIST_S2
Benign
0.44
T
M_CAP
Benign
0.040
D
MetaRNN
Benign
0.12
T
MetaSVM
Uncertain
-0.082
T
PhyloP100
1.9
PrimateAI
Benign
0.31
T
PROVEAN
Benign
0.080
N
REVEL
Benign
0.26
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0
D
Vest4
0.29
MutPred
0.40
Gain of sheet (P = 0.1208);
MVP
0.87
MPC
0.64
ClinPred
0.39
T
GERP RS
5.3
gMVP
0.36
Mutation Taster
=91/9
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.050
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs369437823; hg19: chr11-44129237; API