rs1554580140

Variant names:

• chr8-117837105-T-G
• rs1554580140
• NM_000127.3:c.1056+3A>C

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PP3 PP5_Moderate

The NM_000127.3(EXT1):​c.1056+3A>C variant causes a splice region, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: EXT1 NM_000127.3 splice_region, intron
• Scores: Splicing: ADA: 0.9994
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.75
• 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: Uncertain_significance. The variant received 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 8-117837105-T-G is Pathogenic according to our data. Variant chr8-117837105-T-G is described in ClinVar as Pathogenic. ClinVar VariationId is 456060.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000127.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	EXT1	NM_000127.3	MANE Select	c.1056+3A>C		splice_region intron	N/A	NP_000118.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	EXT1	ENST00000378204.7	TSL:1 MANE Select	c.1056+3A>C		splice_region intron	N/A	ENSP00000367446.3	Q16394
	EXT1	ENST00000436216.2	TSL:3	n.423+3A>C		splice_region intron	N/A	ENSP00000400372.1	H7C1H6
	EXT1	ENST00000437196.1	TSL:5	n.74-1554A>C		intron	N/A	ENSP00000407299.1	F8WF54

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Multiple congenital exostosis (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.25
CADD	Benign	22
DANN	Benign	0.96
PhyloP100		7.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Mutation Taster		=20/80	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.97
SpliceAI score (max)		0.48		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.48		Position offset: 3

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

Other links and lift over

dbSNP: rs1554580140; hg19: chr8-118849344;