rs1555002457

chr11-44107950-CG-Cchr11-44107950-CG-CGG

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_207122.2(EXT2):c.244del(p.Asp82IlefsTer30) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,886 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: EXT2 NM_207122.2 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.83

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 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 11-44107950-CG-C is Pathogenic according to our data. Variant chr11-44107950-CG-C is described in ClinVar as [Pathogenic]. Clinvar id is 465699.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-44107950-CG-C is described in Lovd as [Likely_pathogenic]. Variant chr11-44107950-CG-C is described in Lovd as [Likely_pathogenic]. Variant chr11-44107950-CG-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
EXT2	NM_207122.2	c.244del	p.Asp82IlefsTer30	frameshift_variant	2/14	ENST00000533608.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
EXT2	ENST00000533608.7	c.244del	p.Asp82IlefsTer30	frameshift_variant	2/14	1	NM_207122.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461886 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Exostoses, multiple, type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Apr 04, 2022

This sequence change creates a premature translational stop signal (p.Asp82Ilefs*30) 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 multiple osteochondromatosis (PMID: 18666861, 25449079). It has also been observed to segregate with disease in related individuals. This variant is also known as 239-244delG. ClinVar contains an entry for this variant (Variation ID: 465699). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

LitVar

Other links and lift over

dbSNP: rs1555002457; hg19: chr11-44129500;