chr12-49026426-C-T

Variant names:

• chr12-49026426-C-T
• rs149393179
• NM_003482.4:c.15540G>A

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PM2 BP4_Strong BP6 BP7

The NM_003482.4(KMT2D):​c.15540G>A​(p.Val5180Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. V5180V) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KMT2D NM_003482.4 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: -2.42
• 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, MODERATE Submitted by: Illumina, G2P
• Kabuki syndrome 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Laboratory for Molecular Medicine, ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics
• 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

ACMG classification

Our verdict: Likely_benign. The variant received -4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.61).
• BP6: Variant 12-49026426-C-T is Benign according to our data. Variant chr12-49026426-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2635222.
• BP7: Synonymous conserved (PhyloP=-2.41 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KMT2D	NM_003482.4	c.15540G>A	p.Val5180Val	synonymous_variant	Exon 49 of 55	ENST00000301067.12	NP_003473.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KMT2D	ENST00000301067.12	c.15540G>A	p.Val5180Val	synonymous_variant	Exon 49 of 55	5	NM_003482.4	ENSP00000301067.7

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

KMT2D-related disorder Uncertain:1

Nov 19, 2022

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The KMT2D c.15540G>A variant is not predicted to result in an amino acid change (p.=). This variant is predicted to create a cryptic splice site based on available splicing prediction programs (Alamut Visual Plus v1.6.1). However, such computer prediction programs are imperfect. To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Kabuki syndrome Benign:1

Jun 15, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.61
CADD	Benign	1.3
DANN	Benign	0.72
PhyloP100		-2.4
PromoterAI		-0.0026	Neutral
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.7

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

Other links and lift over

dbSNP: rs149393179; hg19: chr12-49420209;