chr11-118511950-G-A

Variant names:

• chr11-118511950-G-A
• NM_001197104.2:c.11072-1G>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001197104.2(KMT2A):​c.11072-1G>A variant causes a splice acceptor, intron 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2A NM_001197104.2 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.52
• Publications: 0 publications found

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]

TTC36-AS1 (HGNC:55495): (TTC36 and KMT2A antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.006292474 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KMT2A	NM_001197104.2	c.11072-1G>A		splice_acceptor_variant, intron_variant	Intron 30 of 35	ENST00000534358.8	NP_001184033.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KMT2A	ENST00000534358.8	c.11072-1G>A		splice_acceptor_variant, intron_variant	Intron 30 of 35	1	NM_001197104.2	ENSP00000436786.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Wiedemann-Steiner syndrome Uncertain:1

May 02, 2023

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: curation

The heterozygous c.11072-1G>A variant in KMT2A was identified by our study in one individual with partial agenesis of the corpus callosum and moderate global developmental delay. Trio exome analysis revealed this variant to be de novo. The c.11072-1G>A variant in KMT2A has not been previously reported in individuals with Wiedemann-Steiner syndrome. This variant was absent from large population studies. This variant is located in the 3' splice region. Computational tools predict a splicing impact, though this information is not predictive enough to determine pathogenicity. There is an in-frame cryptic splice site 75 bases from the intron-exon boundary, providing evidence that this variant may delete 25 amino acids instead of causing loss of function. However, this information is not predictive enough to determine pathogenicity. Heterozygous loss of function of the KMT2A gene is an established disease mechanism in Wiedemann-Steiner syndrome. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PVS1_Moderate, PS2_Moderate, PM2_Supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
PhyloP100		9.5
GERP RS		5.6
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.99		Position offset: 1

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

Other links and lift over

hg19: chr11-118382665;