chr12-49044262-CGT-C

Position:

• chr12-49044262-CGT-C

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.5124_5125del​(p.Arg1709HisfsTer25) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T1708T) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 4.29

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 12-49044262-CGT-C is Pathogenic according to our data. Variant chr12-49044262-CGT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 286876.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-49044262-CGT-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KMT2D	NM_003482.4	c.5124_5125del	p.Arg1709HisfsTer25	frameshift_variant	22/55	ENST00000301067.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KMT2D	ENST00000301067.12	c.5124_5125del	p.Arg1709HisfsTer25	frameshift_variant	22/55	5	NM_003482.4	A2

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/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kabuki syndrome 1 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	research	Baylor-Hopkins Center for Mendelian Genomics, Johns Hopkins University School of Medicine	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein	Jan 27, 2022	ACMG classification criteria: PVS1 very strong, PS4 supporting, PM2 moderate -
Pathogenic, criteria provided, single submitter	clinical testing	Centre for Mendelian Genomics, University Medical Centre Ljubljana	Jan 30, 2020	This variant was classified as: Pathogenic. The following ACMG criteria were applied in classifying this variant: PVS1,PM2,PP5. -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Sep 11, 2020	This variant is expected to result in the loss of a functional protein This variant has been previously identified in Kabuki patients and occurred de novo in an individual tested at Athena Diagnostics, who had clinical features associated with the KMT2D gene (PMID: 29255178, 22126750). This variant has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org).This observation is not an independent occurrence and has been identified in the same individual by RCIGM, the other laboratory participating in the GEMINI study. -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 11, 2016	- -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 18, 2020

The c.5124_5125delAC (p.R1709Hfs*25) alteration, located in coding exon 21 of the KMT2D gene, consists of a deletion of 2 nucleotides from position 5124 to 5125, causing a translational frameshift with a predicted alternate stop codon after 25 amino acids. Frameshift alterations are typically deleterious in nature (Richards, 2015). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from the Genome Aggregation Database (gnomAD), the KMT2D c.5124_5125delAC alteration was not observed, with coverage at this position. This alteration has been reported once in two separate cohorts of patients with a clinical diagnosis of Kabuki syndrome (Banka, 2012; Sobreira, 2017). Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs886043506; hg19: chr12-49438045;