12-49021873-CTGAA-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1_Strong PM2 PP3_Moderate PP5_Moderate

The NM_003482.4(KMT2D):c.16522-5_16522-2del variant causes a splice acceptor, splice polypyrimidine tract, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 splice_acceptor, splice_polypyrimidine_tract, intron
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.93

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 10 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.17419045 fraction of the gene.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 12-49021873-CTGAA-C is Pathogenic according to our data. Variant chr12-49021873-CTGAA-C is described in ClinVar as [Pathogenic]. Clinvar id is 1301886.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KMT2D	NM_003482.4	c.16522-5_16522-2del		splice_acceptor_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000301067.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KMT2D	ENST00000301067.12	c.16522-5_16522-2del		splice_acceptor_variant, splice_polypyrimidine_tract_variant, intron_variant		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

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Kabuki syndrome 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego

Aug 12, 2020

This variant affects the canonical splice acceptor site of intron 53 and is therefore predicted to interfere with splicing and result in loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay (NMD). This variant has not been previously reported or functionally characterized in the literature to our knowledge. This alteration is located at the C-terminal portion of KMT2D that includes the SET domain with histone methyltransferase activity (PMID: 28669924). Other splicing alterations within intron 53 have been reported in individuals with Kabuki Syndrome (PMID: 28475860, 29304373). This variant is absent from the gnomAD population database and thus is presumed to be rare. Analysis of the parental samples was negative for the variant, indicating this variant likely occurred as a de novo event. Based on the available evidence, the c.16522-5_16522-2del variant is classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.37		Position offset: -19
DS_AL_spliceai		1.0		Position offset: -1

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr12-49415656;