NM_000127.3:c.528_535delCAAAGTGC

Variant names:

• chr8-118110511-TGCACTTTG-T
• rs587776540
• NM_000127.3:c.528_535delCAAAGTGC

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_000127.3(EXT1):​c.528_535delCAAAGTGC​(p.Lys177GlufsTer9) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (no stars). Synonymous variant affecting the same amino acid position (i.e. S176S) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: EXT1 NM_000127.3 frameshift
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.91
• Publications: 0 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 11 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 8-118110511-TGCACTTTG-T is Pathogenic according to our data. Variant chr8-118110511-TGCACTTTG-T is described in ClinVar as Pathogenic. ClinVar VariationId is 2497.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
EXT1	NM_000127.3	c.528_535delCAAAGTGC	p.Lys177GlufsTer9	frameshift_variant	Exon 1 of 11	ENST00000378204.7	NP_000118.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
EXT1	ENST00000378204.7	c.528_535delCAAAGTGC	p.Lys177GlufsTer9	frameshift_variant	Exon 1 of 11	1	NM_000127.3	ENSP00000367446.3
EXT1	ENST00000437196.1	n.73+455_73+462delCAAAGTGC		intron_variant	Intron 1 of 9	5		ENSP00000407299.1
EXT1	ENST00000436216.2	n.-106_-99delCAAAGTGC		upstream_gene_variant		3		ENSP00000400372.1

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Chondrosarcoma Pathogenic:1

Jan 01, 1997

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.9
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs587776540; hg19: chr8-119122750;