19-35718106-G-A

Position:

• chr19-35718106-G-A

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4 BS1_Supporting BS2

The NM_014727.3(KMT2B):​c.88G>A​(p.Gly30Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00017 in 146,744 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.00017 (0 hom., cov: 32)
• Consequence: KMT2B NM_014727.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.294

Genes affected

KMT2B (HGNC:15840): (lysine methyltransferase 2B) This gene encodes a protein which contains multiple domains including a CXXC zinc finger, three PHD zinc fingers, two FY-rich domains, and a SET (suppressor of variegation, enhancer of zeste, and trithorax) domain. The SET domain is a conserved C-terminal domain that characterizes proteins of the MLL (mixed-lineage leukemia) family. This gene is ubiquitously expressed in adult tissues. It is also amplified in solid tumor cell lines, and may be involved in human cancer. Two alternatively spliced transcript variants encoding distinct isoforms have been reported for this gene, however, the full length nature of the shorter transcript is not known. [provided by RefSeq, Jul 2008]

KMT2B (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.31663).
• BS1: Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.00017 (25/146744) while in subpopulation AMR AF= 0.00162 (24/14786). AF 95% confidence interval is 0.00112. There are 0 homozygotes in gnomad4. There are 16 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 25 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KMT2B	NM_014727.3	c.88G>A	p.Gly30Ser	missense_variant	1/37	ENST00000420124.4	NP_055542.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KMT2B	ENST00000420124.4	c.88G>A	p.Gly30Ser	missense_variant	1/37	1	NM_014727.3	ENSP00000398837.2
KMT2B	ENST00000673918.2	c.88G>A	p.Gly30Ser	missense_variant	1/37			ENSP00000501283.1
KMT2B	ENST00000687718.1	n.88G>A		non_coding_transcript_exon_variant	1/3			ENSP00000510535.1
KMT2B	ENST00000692961.1	n.88G>A		non_coding_transcript_exon_variant	1/36			ENSP00000509289.1

Frequencies

GnomAD3 genomes AF: 0.000170 AC: 25 AN: 146744 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00162

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000152

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.000170 AC: 25 AN: 146744 Hom.: 0 Cov.: 32 AF XY: 0.000224 AC XY: 16 AN XY: 71384

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00162

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000152

Gnomad4 OTH AF: 0.00

Bravo AF: 0.000208

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 04, 2023

This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 30 of the KMT2B protein (p.Gly30Ser). 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 variant has not been reported in the literature in individuals affected with KMT2B-related conditions. 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 KMT2B protein function with a positive predictive value of 80%. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.028	T
BayesDel_noAF	Benign	-0.20
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Benign	0.022	T
Eigen	Benign	-0.14
Eigen_PC	Benign	-0.25
FATHMM_MKL	Benign	0.14	N
LIST_S2	Benign	0.45	T
M_CAP	Pathogenic	0.91	D
MetaRNN	Benign	0.32	T
MetaSVM	Benign	-0.46	T
MutationAssessor	Benign	0.0	N
PrimateAI	Pathogenic	0.89	D
PROVEAN	Benign	0.25	N
REVEL	Uncertain	0.31
Sift	Pathogenic	0.0	D
Sift4G	Benign	0.54	T
Polyphen		1.0	D
Vest4		0.35
MutPred		0.26		Gain of glycosylation at G30 (P = 0.0019);
MVP		0.55
ClinPred		0.35	T
GERP RS		2.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8
Varity_R		0.096
gMVP		0.11

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1315348887; hg19: chr19-36209008;