chr11-118503330-C-T

Position:

• chr11-118503330-C-T

Variant summary

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

The NM_001197104.2(KMT2A):​c.7438C>T​(p.Arg2480Ter) 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: KMT2A NM_001197104.2 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 2.02

Genes affected

KMT2A (HGNC:7132): (lysine methyltransferase 2A) This gene encodes a transcriptional coactivator that plays an essential role in regulating gene expression during early development and hematopoiesis. The encoded protein contains multiple conserved functional domains. One of these domains, the SET domain, is responsible for its histone H3 lysine 4 (H3K4) methyltransferase activity which mediates chromatin modifications associated with epigenetic transcriptional activation. This protein is processed by the enzyme Taspase 1 into two fragments, MLL-C and MLL-N. These fragments reassociate and further assemble into different multiprotein complexes that regulate the transcription of specific target genes, including many of the HOX genes. Multiple chromosomal translocations involving this gene are the cause of certain acute lymphoid leukemias and acute myeloid leukemias. Alternate splicing results in multiple transcript variants.[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 11-118503330-C-T is Pathogenic according to our data. Variant chr11-118503330-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 449960.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-118503330-C-T is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KMT2A	NM_001197104.2	c.7438C>T	p.Arg2480Ter	stop_gained	27/36	ENST00000534358.8	NP_001184033.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KMT2A	ENST00000534358.8	c.7438C>T	p.Arg2480Ter	stop_gained	27/36	1	NM_001197104.2	ENSP00000436786	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Wiedemann-Steiner syndrome Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 27, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen	Oct 25, 2021	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics and Genomics, Karolinska University Hospital	Oct 05, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 11, 2022	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 (gnomAD); This variant is associated with the following publications: (PMID: 30305169, 25810209, 29574747, 33004838, 33783954, 28191889) -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 16, 2024

The c.7438C>T (p.R2480*) alteration, located in exon 27 (coding exon 27) of the KMT2A gene, consists of a C to T substitution at nucleotide position 7438. This changes the amino acid from an arginine (R) to a stop codon at amino acid position 2480. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This variant has been detected in multiple individuals with features consistent with Wiedemann-Steiner syndrome, including multiple cases of reported de novo occurrence (Miyake, 2015; Baer, 2018; Sheppard, 2021; Foroutan, 2022). Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Benign	0.17
Eigen_PC	Benign	-0.013
FATHMM_MKL	Uncertain	0.83	D
MutationTaster	Benign	1.0	A;A;A
Vest4		0.87
GERP RS		2.8
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: rs1555046568; hg19: chr11-118374045;