20-32806253-A-C

Position:

• chr20-32806253-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 5P and 2B. PM1 PM2 PP2 BP4_Moderate

The NM_006892.4(DNMT3B):​c.2346A>C​(p.Lys782Asn) variant causes a missense 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: DNMT3B NM_006892.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.50

Genes affected

DNMT3B (HGNC:2979): (DNA methyltransferase 3 beta) CpG methylation is an epigenetic modification that is important for embryonic development, imprinting, and X-chromosome inactivation. Studies in mice have demonstrated that DNA methylation is required for mammalian development. This gene encodes a DNA methyltransferase which is thought to function in de novo methylation, rather than maintenance methylation. The protein localizes primarily to the nucleus and its expression is developmentally regulated. Mutations in this gene cause the immunodeficiency-centromeric instability-facial anomalies (ICF) syndrome. Eight alternatively spliced transcript variants have been described. The full length sequences of variants 4 and 5 have not been determined. [provided by RefSeq, May 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a domain SAM-dependent MTase C5-type (size 278) in uniprot entity DNM3B_HUMAN there are 27 pathogenic changes around while only 1 benign (96%) in NM_006892.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), DNMT3B. . Gene score misZ 1.5 (greater than the threshold 3.09). Trascript score misZ 3.3234 (greater than threshold 3.09). GenCC has associacion of gene with immunodeficiency-centromeric instability-facial anomalies syndrome, immunodeficiency-centromeric instability-facial anomalies syndrome 1.
• BP4: Computational evidence support a benign effect (MetaRNN=0.24466735).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DNMT3B	NM_006892.4	c.2346A>C	p.Lys782Asn	missense_variant	22/23	ENST00000328111.6	NP_008823.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DNMT3B	ENST00000328111.6	c.2346A>C	p.Lys782Asn	missense_variant	22/23	1	NM_006892.4	ENSP00000328547	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Centromeric instability of chromosomes 1,9 and 16 and immunodeficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 06, 2020

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with DNMT3B-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces lysine with asparagine at codon 782 of the DNMT3B protein (p.Lys782Asn). The lysine residue is weakly conserved and there is a moderate physicochemical difference between lysine and asparagine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Benign	-0.016	T
BayesDel_noAF	Benign	-0.26
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.62	D;.;.
Eigen	Benign	0.093
Eigen_PC	Benign	0.20
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Uncertain	0.97	D;D;D
M_CAP	Uncertain	0.11	D
MetaRNN	Benign	0.24	T;T;T
MetaSVM	Uncertain	0.67	D
MutationAssessor	Uncertain	2.1	M;.;.
MutationTaster	Benign	1.0	D;D;D;D;N;N;N
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-3.5	D;D;D
REVEL	Uncertain	0.48
Sift	Uncertain	0.010	D;D;D
Sift4G	Uncertain	0.017	D;D;D
Polyphen		0.034	B;B;B
Vest4		0.25
MutPred		0.54		Loss of methylation at K782 (P = 8e-04);.;.;
MVP		0.92
MPC		0.97
ClinPred		0.97	D
GERP RS		4.3
Varity_R		0.81
gMVP		0.65

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: rs1555842652; hg19: chr20-31394059;