chr9-137776684-C-T

Position:

• chr9-137776684-C-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_024757.5(EHMT1):​c.1858C>T​(p.Arg620*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: EHMT1 NM_024757.5 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5 O:1
• Conservation: PhyloP100: 2.43

Genes affected

EHMT1 (HGNC:24650): (euchromatic histone lysine methyltransferase 1) The protein encoded by this gene is a histone methyltransferase that methylates the lysine-9 position of histone H3. This action marks the genomic region packaged with these methylated histones for transcriptional repression. This protein may be involved in the silencing of MYC- and E2F-responsive genes and therefore could play a role in the G0/G1 cell cycle transition. Defects in this gene are a cause of chromosome 9q subtelomeric deletion syndrome (9q-syndrome, also known as Kleefstra syndrome). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2017]

ENSG00000255585 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 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 9-137776684-C-T is Pathogenic according to our data. Variant chr9-137776684-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 65729.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
EHMT1	NM_024757.5	c.1858C>T	p.Arg620*	stop_gained	12/27	ENST00000460843.6	NP_079033.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
EHMT1	ENST00000460843.6	c.1858C>T	p.Arg620*	stop_gained	12/27	5	NM_024757.5	ENSP00000417980.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kleefstra syndrome 1 Pathogenic:3 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Department of Genetics, Rouen University Hospital, Normandy Center for Genomic and Personalized Medicine	Aug 11, 2021	- -
Pathogenic, criteria provided, single submitter	curation	Laboratory of Genetics, Children's Clinical University Hospital Latvia	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Oct 08, 2024	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Kleefstra syndrome 1 (MIM#610253). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0201 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction). (SP) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0701 - Other NMD-predicted variants comparable to the one identified in this case have very strong previous evidence for pathogenicity. There are many NMD-predicted variants which have been reported as pathogenic (ClinVar). (SP) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been reported as pathogenic in ClinVar in individuals affected with Kleefstra syndrome 1. This variant was also identified in two unrelated individuals diagnosed with Kleefstra syndrome 1 (PMID:22670141). (SP) 1007 - No published functional evidence has been identified for this variant. (I) 1203 - This variant has been shown to be de novo in the proband (parental status confirmed) by trio analysis. (SP) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
not provided, no classification provided	literature only	GeneReviews	-	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 23, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 30, 2021	Reported previously in individuals with Kleefstra syndrome (Willemsen et al., 2012); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 22670141) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Pathogenic	0.79
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.84	D
Vest4		0.89
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs137852718; hg19: chr9-140671136;