rs587783690

Positions:

• chr12-49031255-G-A
• chr12-49031255-G-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.13450C>T​(p.Arg4484Ter) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000685 in 1,460,742 control chromosomes in the GnomAD database, with no homozygous occurrence. 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)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KMT2D NM_003482.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 5.67

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 12-49031255-G-A is Pathogenic according to our data. Variant chr12-49031255-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 158729.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-49031255-G-A is described in Lovd as [Pathogenic]. Variant chr12-49031255-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KMT2D	NM_003482.4	c.13450C>T	p.Arg4484Ter	stop_gained	40/55	ENST00000301067.12	NP_003473.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KMT2D	ENST00000301067.12	c.13450C>T	p.Arg4484Ter	stop_gained	40/55	5	NM_003482.4	ENSP00000301067	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460742 Hom.: 0 Cov.: 39 AF XY: 0.00000138 AC XY: 1 AN XY: 726688

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kabuki syndrome 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 08, 2013	- -
Pathogenic, no assertion criteria provided	clinical testing	Autoinflammatory diseases unit, CHU de Montpellier	Apr 30, 2015	- -

Kabuki syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 21, 2023

For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Arg4484*) in the KMT2D gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in KMT2D are known to be pathogenic (PMID: 22126750). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with Kabuki syndrome (PMID: 21280141, 27302555, 29283410). ClinVar contains an entry for this variant (Variation ID: 158729). -

Inborn genetic diseases Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 26, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	46
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.96	D
MutationTaster	Benign	1.0	A
Vest4		0.77
GERP RS		5.6
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: rs587783690; hg19: chr12-49425038; COSMIC: COSV56434635; COSMIC: COSV56434635;