rs1555191598

Positions:

• chr12-49039605-G-A
• chr12-49039605-G-C
• chr12-49039605-G-T

Variant summary

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

The NM_003482.4(KMT2D):​c.8059C>T​(p.Arg2687Ter) 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 Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KMT2D NM_003482.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 3.54

Genes affected

KMT2D (HGNC:7133): (lysine methyltransferase 2D) The protein encoded by this gene is a histone methyltransferase that methylates the Lys-4 position of histone H3. The encoded protein is part of a large protein complex called ASCOM, which has been shown to be a transcriptional regulator of the beta-globin and estrogen receptor genes. Mutations in this gene have been shown to be a cause of Kabuki syndrome. [provided by RefSeq, Oct 2010]

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 12-49039605-G-A is Pathogenic according to our data. Variant chr12-49039605-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 449562.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-49039605-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KMT2D	NM_003482.4	c.8059C>T	p.Arg2687Ter	stop_gained	33/55	ENST00000301067.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KMT2D	ENST00000301067.12	c.8059C>T	p.Arg2687Ter	stop_gained	33/55	5	NM_003482.4	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kabuki syndrome 1 Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Jul 11, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Lifecell International Pvt. Ltd	-	A Heterozygous Nonsense variant c.8059C>T in Exon 33 of the KMT2D gene that results in the amino acid substitution p.Arg2687* was identified. The observed variant is novel in gnomAD exomes and genomes. The severity of the impact of this variant on the protein is high, based on the effect of the protein and REVEL score . Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. ClinVar has also classified this variant as Pathogenic [Variant ID :449562]. For these reasons this variant has been classified as Likely Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital	-	The heterozygous de-novo variant c.8059C>T (p.Arg2687*) is identified in a proband with atrial septal defect, cleft palate, coronal craniosynostosis, bilateral coloboma, micrognathia, pyriform aperture stenosis. This stop gain variant is predicted to cause NMD in the gene KMT2D where loss of function is a known mechanism (PVS1_very strong). This variant has not been identified in gnomAD population database (PM2_moderate). However, this has been reported in ClinVar id 449562 thrice (PP5_supporting). -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Aug 02, 2019

Reported previously, in the heterozygous state, in one individual with Kabuki syndrome (Banka 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 in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 22126750) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	45
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.95
FATHMM_MKL	Uncertain	0.95	D
MutationTaster	Benign	1.0	A
Vest4		0.82
GERP RS		5.6
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: rs1555191598; hg19: chr12-49433388; COSMIC: COSV56441698; COSMIC: COSV56441698;