rs1555185217

chr12-49024578-C-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_003482.4(KMT2D):c.16052G>A(p.Arg5351Gln) variant causes a missense, splice region 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R5351W) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.91

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 17 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-49024579-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2690981.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP2: Missense variant where missense usually causes diseases, KMT2D
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 12-49024578-C-T is Pathogenic according to our data. Variant chr12-49024578-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 463012.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-49024578-C-T is described in Lovd as [Pathogenic]. Variant chr12-49024578-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KMT2D	NM_003482.4	c.16052G>A	p.Arg5351Gln	missense_variant, splice_region_variant	51/55	ENST00000301067.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KMT2D	ENST00000301067.12	c.16052G>A	p.Arg5351Gln	missense_variant, splice_region_variant	51/55	5	NM_003482.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kabuki syndrome 1 Pathogenic:2

Pathogenic, no assertion criteria provided	clinical testing	Autoinflammatory diseases unit, CHU de Montpellier	Jun 10, 2014	- -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Sep 02, 2022	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with Kabuki syndrome 1 (MIM#147920). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to glutamine. This variant is also in a splice region as it affects the last coding base of an exon. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0309 - Multiple alternative amino acid changes at the same position have been observed in gnomAD (highest allele count: 2 heterozygotes, 0 homozygotes). However, one of these heterozygotes is poor quality. (I) 0502 - Missense variant with conflicting in silico predictions and high conservation. Abnormal splicing is predicted by in silico tools. (I) 0603 - Missense variant in a region that is highly intolerant to missense variation (high constraint region in DECIPHER). (SP) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. This variant has been classified as pathogenic by two clinical laboratories in ClinVar, including one de novo individual with Kabuki syndrome who was also reported in the literature (PMID: 27302555). This variant has also been observed in two other individuals with Kabuki syndrome in the literature, including another de novo case (PMIDs: 23913813, 28475860). (SP) 1101 - Very strong and specific phenotype match for this individual. (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Kabuki syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Apr 23, 2023

For these reasons, this variant has been classified as Pathogenic. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. ClinVar contains an entry for this variant (Variation ID: 463012). This missense change has been observed in individual(s) with clinical features of Kabuki syndrome (PMID: 23913813, 26785492, 27302555). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 5351 of the KMT2D protein (p.Arg5351Gln). This variant also falls at the last nucleotide of exon 50, which is part of the consensus splice site for this exon. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Uncertain	0.0
Cadd	Pathogenic	30
Dann	Uncertain	1.0
DEOGEN2	Benign	0.032	T
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.55	T
M_CAP	Pathogenic	0.79	D
MetaRNN	Pathogenic	0.79	D
MetaSVM	Uncertain	0.29	D
MutationTaster	Benign	1.0	D
PROVEAN	Benign	-2.0	N
REVEL	Pathogenic	0.73
Sift	Uncertain	0.015	D
Sift4G	Uncertain	0.017	D
MutPred		0.46		Loss of MoRF binding (P = 0.0195);
MVP		0.95
ClinPred		0.97	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.73		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.73		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555185217; hg19: chr12-49418361; COSMIC: COSV56494348;