Genetic Variant EXT1:p.Gln732Pro (chr8-117799758-T-G) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

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

The NM_000127.3(EXT1):c.2195A>C(p.Gln732Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q732R) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

EXT1
NM_000127.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 8.02

Publications

0 publications found

Variant links:

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

EXT1 links:

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ACMG classification

Classification was made for transcript

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
EXT1	NM_000127.3 link	c.2195A>C	p.Gln732Pro	missense_variant	Exon 11 of 11	ENST00000378204.7	NP_000118.2	Q16394

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
EXT1	ENST00000378204.7 link	c.2195A>C	p.Gln732Pro	missense_variant	Exon 11 of 11	1	NM_000127.3	ENSP00000367446.3	Q16394
EXT1	ENST00000684189.1 link	n.1662A>C		non_coding_transcript_exon_variant	Exon 11 of 11
EXT1	ENST00000684443.1 link	n.2321A>C		non_coding_transcript_exon_variant	Exon 2 of 2
EXT1	ENST00000437196.1 link	n.*1086A>C		downstream_gene_variant		5		ENSP00000407299.1	F8WF54

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.24

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.43

CADD

Uncertain

(source)

DANN

Benign

0.22

DEOGEN2

Benign

0.30

Eigen

Benign

-0.085

Eigen_PC

Benign

0.17

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.91

M_CAP

Benign

0.045

MetaRNN

Uncertain

0.49

MetaSVM

Uncertain

0.17

MutationAssessor

Benign

0.97

PhyloP100

8.0

PrimateAI

Uncertain

0.75

PROVEAN

Benign

1.1

REVEL

Uncertain

0.41

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.0020

Vest4

0.84

MutPred

0.35

Gain of relative solvent accessibility (P = 0.0522);

MVP

0.96

MPC

1.6

ClinPred

0.96

GERP RS

6.0

Varity_R

0.25

gMVP

0.77

Mutation Taster

=20/80

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over