NM_001440.4:c.953C>T

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong

The NM_001440.4(EXTL3):​c.953C>T​(p.Pro318Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000867 in 1,614,144 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 (★★). Synonymous variant affecting the same amino acid position (i.e. P318P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

EXTL3
NM_001440.4 missense

Scores

12
3
4

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 7.73

Publications

8 publications found
Variant links:
Genes affected
EXTL3 (HGNC:3518): (exostosin like glycosyltransferase 3) This gene encodes a single-pass membrane protein which functions as a glycosyltransferase. The encoded protein catalyzes the transfer of N-acetylglucosamine to glycosaminoglycan chains. This reaction is important in heparin and heparan sulfate synthesis. Alternative splicing results in the multiple transcript variants. [provided by RefSeq, Nov 2012]
EXTL3 Gene-Disease associations (from GenCC):
  • immunoskeletal dysplasia with neurodevelopmental abnormalities
    Inheritance: AR Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 14 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.971
PP5
Variant 8-28717012-C-T is Pathogenic according to our data. Variant chr8-28717012-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 623480.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
EXTL3NM_001440.4 linkc.953C>T p.Pro318Leu missense_variant Exon 3 of 7 ENST00000220562.9 NP_001431.1 O43909A0A384NPY9

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
EXTL3ENST00000220562.9 linkc.953C>T p.Pro318Leu missense_variant Exon 3 of 7 1 NM_001440.4 ENSP00000220562.4 O43909

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152260
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:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251256
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000881
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000889
AC:
13
AN:
1461884
Hom.:
0
Cov.:
31
AF XY:
0.00000688
AC XY:
5
AN XY:
727238
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000989
AC:
11
AN:
1112008
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.540
Heterozygous variant carriers
0
2
3
5
6
8
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:
0.00000657
AC:
1
AN:
152260
Hom.:
0
Cov.:
32
AF XY:
0.0000134
AC XY:
1
AN XY:
74386
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41470
American (AMR)
AF:
0.00
AC:
0
AN:
15288
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5204
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68048
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
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:
0.0000712
Hom.:
0
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not provided Pathogenic:1
Mar 25, 2019
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Published functional studies demonstrate a damaging effect with significantly decreased enzyme activity compared to wild type (Guo et al., 2017); Not observed at a significant frequency in large population cohorts (Lek et al., 2016; McVean et al., 2012; Exome Variant Server); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 28331220) -

Immunoskeletal dysplasia with neurodevelopmental abnormalities Pathogenic:1
Mar 13, 2019
Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The observed variant NM_001440.3:c.953C>T/p.Pro318Leu is a homozygous missense variation in exon 3 of the EXTL3 gene. It has not been reported in the 1000 Genomes and ExAC databases but has been reported as a pathogenic variant by Guo. et al (2017). The in silico prediction of this variant is disease causing by PolyPhen-2, SIFT, LRT and MutationTaster2. The reference codon is conserved across species. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.76
BayesDel_addAF
Pathogenic
0.46
D
BayesDel_noAF
Pathogenic
0.42
CADD
Uncertain
25
DANN
Uncertain
0.99
DEOGEN2
Pathogenic
0.83
D
Eigen
Uncertain
0.27
Eigen_PC
Benign
0.18
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
0.98
D
M_CAP
Pathogenic
0.59
D
MetaRNN
Pathogenic
0.97
D
MetaSVM
Pathogenic
0.90
D
MutationAssessor
Uncertain
2.6
M
PhyloP100
7.7
PrimateAI
Pathogenic
0.83
D
PROVEAN
Pathogenic
-4.8
D
REVEL
Pathogenic
0.83
Sift
Benign
0.16
T
Sift4G
Benign
0.13
T
Polyphen
0.97
D
Vest4
0.95
MutPred
0.73
Gain of sheet (P = 0.0827);
MVP
0.96
MPC
0.95
ClinPred
0.94
D
GERP RS
4.3
Varity_R
0.26
gMVP
0.88
Mutation Taster
=9/91
disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs749621890; hg19: chr8-28574529; API