chr12-49046746-ACA-TCC

Variant names:

• chr12-49046746-ACA-TCC
• NM_003482.4:c.4279_4281delTGTinsGGA
• KMT2D p.Cys1427Gly

GermlineCancer (beta)

Variant summary

Our verdict is Uncertain significance.

+4 Uncertain · Hot

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 4 classification points (ACGS-UK Somatic Oncogenicity v2025). O3_ModerateO5_SupportingO7_Supporting

The NM_003482.4(KMT2D):c.4279_4281delTGTinsGGA (p.Cys1427Gly) variant causes a missense change. The gene KMT2D is a tumor suppressor gene (CancerMine: 29 TSG, 29 oncogene, 10 driver citations). The gene KMT2D is a known oncogene (CancerMine: 29 TSG, 29 oncogene, 10 driver citations). The gene KMT2D is a cancer driver gene (CancerMine: 29 TSG, 29 oncogene, 10 driver citations). Note: allele frequency estimates from gnomAD may be inaccurate for this variant type (MNP or indel longer than 3 bp) due to technology limitations. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 9.20). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.C1427Y: Likely_pathogenic (ClinVar VariationId 521566, 1 star)

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.20
• Publications: 0 publications found

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]

KMT2D Gene-Disease associations (from GenCC):

• choanal atresia-athelia-hypothyroidism-delayed puberty-short stature syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Illumina, PanelApp Australia
• Kabuki syndrome 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), PanelApp Australia, Laboratory for Molecular Medicine, ClinGen
• branchial arch abnormalities, choanal atresia, athelia, hearing loss, and hypothyroidism syndrome

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• Kabuki syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Classification according to ACGS-UK Somatic Oncogenicity v2025

Classification was made for transcript:

Our verdict: Uncertain_significance. The variant received 4 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O3Absent or very rare in population		Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = absent, AC = 0 — absent/extremely rare (O3 moderate [+2])
	O5Same location/impact as known oncogenic		Different AA at same residue with oncogenic evidence (or germline P/LP in TSG), or same AA change SCI Tier II Potential — Supporting (O5); ClinVar same-AA oncogenic/T1: false | ClinVar same-AA SCI tier: — | CGI same-AA oncogenic: false | TSG: true | ClinVar same-AA germline P/LP: false | CIViC LOF: false | ClinVar diff-AA oncogenic: false | ClinVar diff-AA germline P/LP: true
	O7Mutational hotspot or critical domain		Supporting: cancerhotspots.org hit, critical domain, or missense neighbourhood hotspot; No cancerhotspots.org hit at this position; UniProt domain: 0 pathogenic, 0 benign.; ±8 AA neighbourhood: 5 pathogenic, 0 benign (OR vs. background: 55.0); Variant does not impact splicing — splice-hotspot path not applicable

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_003482.4. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KMT2D NM_003482.4	MANE Select	c.4279_4281delTGTinsGGA p.Cys1427Gly	missense	N/A	Prot: NP_003473.3 UniProt:

KMT2D NM_003482.4

MANE Select

HGVSc / HGVSpc.4279_4281delTGTinsGGAp.Cys1427Gly

Exon rankN/A

missense

Prot: NP_003473.3UniProt: O14686-1

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	KMT2D ENST00000301067.12	TSL:5MANE Select	c.4279_4281delTGTinsGGA p.Cys1427Gly	missense	N/A	Prot: ENSP00000301067.7 UniProt:
	KMT2D ENST00000683543.2		c.4279_4281delTGTinsGGA p.Cys1427Gly	missense	N/A	Prot: ENSP00000506726.1 UniProt:
	KMT2D ENST00000685166.1		c.4279_4281delTGTinsGGA p.Cys1427Gly	missense	N/A	Prot: ENSP00000509386.1 UniProt:

KMT2D ENST00000301067.12

TSL:5MANE Select

HGVSc / HGVSpc.4279_4281delTGTinsGGAp.Cys1427Gly

Exon rankN/A

missense

Prot: ENSP00000301067.7UniProt: O14686-1

KMT2D ENST00000683543.2

HGVSc / HGVSpc.4279_4281delTGTinsGGAp.Cys1427Gly

Exon rankN/A

missense

Prot: ENSP00000506726.1UniProt: A0A804HHR9

KMT2D ENST00000685166.1

HGVSc / HGVSpc.4279_4281delTGTinsGGAp.Cys1427Gly

Exon rankN/A

missense

Prot: ENSP00000509386.1UniProt: O14686-3

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 2 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:32
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:32

Showing 2 sources

Tested, but no data found:GnomAD4 exomeIf GnomAD4 is missing, the position is probably not covered by the project.

ClinVar

Not reported in ClinVar

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
PhyloP100	Pathogenic	9.2

Showing 1 of 1 scores

Splicing Scores

No splicing scores have been computed for this variant.

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

No MaveDB functional evidence found for this variant.

Other links and lift over

hg19: chr12-49440529;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar