12-49046684-C-T

Position:

• chr12-49046684-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_003482.4(KMT2D):​c.4343G>A​(p.Cys1448Tyr) variant causes a missense 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. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1448W) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• 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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a zinc_finger_region PHD-type 5 (size 50) in uniprot entity KMT2D_HUMAN there are 16 pathogenic changes around while only 3 benign (84%) in NM_003482.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), KMT2D. . Gene score misZ 3.7288 (greater than the threshold 3.09). Trascript score misZ 4.6964 (greater than threshold 3.09). GenCC has associacion of gene with Kabuki syndrome, branchial arch abnormalities, choanal atresia, athelia, hearing loss, and hypothyroidism syndrome, Kabuki syndrome 1, choanal atresia-athelia-hypothyroidism-delayed puberty-short stature syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KMT2D	NM_003482.4	c.4343G>A	p.Cys1448Tyr	missense_variant	16/55	ENST00000301067.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KMT2D	ENST00000301067.12	c.4343G>A	p.Cys1448Tyr	missense_variant	16/55	5	NM_003482.4	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Kabuki syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 25, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt KMT2D protein function. This variant has been observed in individual(s) with Kabuki syndrome (PMID: 30459467). ClinVar contains an entry for this variant (Variation ID: 158768). This variant is not present in population databases (ExAC no frequency). This sequence change replaces cysteine with tyrosine at codon 1448 of the KMT2D protein (p.Cys1448Tyr). The cysteine residue is highly conserved and there is a large physicochemical difference between cysteine and tyrosine. -

Kabuki syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Feb 08, 2013

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Uncertain	25
DANN	Benign	0.93
DEOGEN2	Benign	0.29	T
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Pathogenic	4.0	H
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-9.4	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.95		Gain of helix (P = 0.027);
MVP		1.0
MPC		3.2
ClinPred		1.0	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.89
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs587783716; hg19: chr12-49440467; COSMIC: COSV56483694; COSMIC: COSV56483694;