chr20-32800239-G-A

Position:

• chr20-32800239-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_006892.4(DNMT3B):​c.1846G>A​(p.Val616Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000752 in 1,461,892 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: not found (cov: 33)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: DNMT3B NM_006892.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.14

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 4 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=0.2963665).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DNMT3B	NM_006892.4	c.1846G>A	p.Val616Met	missense_variant	17/23	ENST00000328111.6	NP_008823.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DNMT3B	ENST00000328111.6	c.1846G>A	p.Val616Met	missense_variant	17/23	1	NM_006892.4	ENSP00000328547.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251496 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135922

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461892 Hom.: 0 Cov.: 35 AF XY: 0.00000963 AC XY: 7 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000450

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

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

Aug 31, 2021

This sequence change replaces valine with methionine at codon 616 of the DNMT3B protein (p.Val616Met). The valine residue is highly conserved and there is a small physicochemical difference between valine and methionine. This variant is present in population databases (rs754182982, ExAC 0.006%). This variant has not been reported in the literature in individuals affected with DNMT3B-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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	Pathogenic	0.63
BayesDel_addAF	Uncertain	0.055	T
BayesDel_noAF	Uncertain	-0.060
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.82	D;.;.;.;.;.
Eigen	Uncertain	0.26
Eigen_PC	Benign	0.17
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.92	D;D;D;D;D;D
M_CAP	Benign	0.036	D
MetaRNN	Benign	0.30	T;T;T;T;T;T
MetaSVM	Uncertain	0.13	D
MutationAssessor	Uncertain	2.4	M;.;.;.;.;.
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-2.7	D;D;D;D;D;D
REVEL	Uncertain	0.49
Sift	Uncertain	0.0020	D;D;D;D;D;D
Sift4G	Uncertain	0.0060	D;D;D;D;D;D
Polyphen		0.86	P;P;P;.;.;P
Vest4		0.23
MutPred		0.36		Loss of methylation at K617 (P = 0.0268);.;.;.;.;.;
MVP		0.81
MPC		1.6
ClinPred		0.96	D
GERP RS		3.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.79
gMVP		0.75

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: rs754182982; hg19: chr20-31388045; COSMIC: COSV52415403;