rs1032612888

Variant names:

• chr11-44096305-A-G
• rs1032612888
• ENST00000343631.4:c.-47A>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_207122.2(EXT2):​c.-31+453A>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000195 in 1,535,810 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 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: EXT2 NM_207122.2 intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.84
• Publications: 0 publications found

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

ACMG classification

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

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.0437645).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
EXT2	NM_207122.2	c.-31+453A>G		intron_variant	Intron 1 of 13	ENST00000533608.7	NP_997005.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
EXT2	ENST00000533608.7	c.-31+453A>G		intron_variant	Intron 1 of 13	1	NM_207122.2	ENSP00000431173.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152138 Hom.: 0 Cov.: 32

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

GnomAD4 exome AF: 0.00000145 AC: 2 AN: 1383672 Hom.: 0 Cov.: 32 AF XY: 0.00000146 AC XY: 1 AN XY: 682800

African (AFR) AF: 0.00 AC: 0 AN: 31590

American (AMR) AF: 0.00 AC: 0 AN: 35698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25170

East Asian (EAS) AF: 0.00 AC: 0 AN: 35724

South Asian (SAS) AF: 0.00 AC: 0 AN: 79222

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33906

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5680

European-Non Finnish (NFE) AF: 0.00000185 AC: 2 AN: 1078792

Other (OTH) AF: 0.00 AC: 0 AN: 57890

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152138 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74342

African (AFR) AF: 0.00 AC: 0 AN: 41426

American (AMR) AF: 0.00 AC: 0 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5186

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68014

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Exostoses, multiple, type 2 Uncertain:1

May 23, 2022

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.53A>G (p.Gln18Arg) missense change is absent in gnomAD v2.1.1 (PM2_supporting; https://gnomad.broadinstitute.org/). It is predicted to have a benign effect on protein function (BP4), but to our knowledge this prediction has not been confirmed by functional assays. To our knowledge, this variant has not been reported in individuals with hereditary multiple exostoses. In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria: PM2_supporting, BP4. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.46
CADD	Benign	1.4
DANN	Benign	0.48
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.7
FATHMM_MKL	Benign	0.0010	N
LIST_S2	Benign	0.23	T
M_CAP	Benign	0.0099	T
MetaRNN	Benign	0.044	T
MetaSVM	Benign	-0.41	T
PhyloP100		-2.8
PrimateAI	Benign	0.29	T
PROVEAN	Benign	0.0	N
REVEL	Benign	0.21
Sift	Benign	0.94	T
Vest4		0.044
MutPred		0.15		Gain of disorder (P = 0.079);
MVP		0.55
MPC		0.23
ClinPred		0.043	T
GERP RS		-5.5
PromoterAI		0.26	Neutral
gMVP		0.66
Mutation Taster		=95/5	polymorphism

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: rs1032612888; hg19: chr11-44117855;