20-10641112-C-T

Position:

• chr20-10641112-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PVS1_Moderate PM2 PP3_Strong PP5

The NM_000214.3(JAG1):​c.3048+1G>A variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: JAG1 NM_000214.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 7.38

Genes affected

JAG1 (HGNC:6188): (jagged canonical Notch ligand 1) The jagged 1 protein encoded by JAG1 is the human homolog of the Drosophilia jagged protein. Human jagged 1 is the ligand for the receptor notch 1, the latter is involved in signaling processes. Mutations that alter the jagged 1 protein cause Alagille syndrome. Jagged 1 signalling through notch 1 has also been shown to play a role in hematopoiesis. [provided by RefSeq, Nov 2019]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.035821714 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 20-10641112-C-T is Pathogenic according to our data. Variant chr20-10641112-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 265204.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
JAG1	NM_000214.3	c.3048+1G>A		splice_donor_variant		ENST00000254958.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
JAG1	ENST00000254958.10	c.3048+1G>A		splice_donor_variant		1	NM_000214.3	P1
JAG1	ENST00000617357.1	n.165G>A		non_coding_transcript_exon_variant	1/2	2
JAG1	ENST00000423891.6	n.2914+1G>A		splice_donor_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jun 12, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 20, 2016	The c.3048+1 G>A splice site variant in the JAG1 gene destroys the canonical splice donor site in intron 24. It is predicted to cause abnormal gene splicing, either leading to an abnormal message that is subject to nonsense-mediated mRNA decay, or to an abnormal protein product if the message is used for protein translation. The variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. -

Alagille syndrome due to a JAG1 point mutation Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 28, 2022

This sequence change affects a donor splice site in intron 24 of the JAG1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with Alagille syndrome (PMID: 15772854). ClinVar contains an entry for this variant (Variation ID: 265204). Studies have shown that disruption of this splice site results in skipping of exon 24, but is expected to preserve the integrity of the reading-frame (PMID: 15772854). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Uncertain	0.96	D
MutationTaster	Benign	1.0	D;D
GERP RS		6.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.95		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs876661121; hg19: chr20-10621760;