20-32800916-G-T

Variant names:

• chr20-32800916-G-T
• rs121908942
• NM_006892.4:c.1987G>T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_006892.4(DNMT3B):​c.1987G>T​(p.Gly663Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G663S) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: DNMT3B NM_006892.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.91

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 Pathogenic. Variant got 11 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
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr20-32800916-G-A is described in Lovd as [Pathogenic].
• PP2: Missense variant in the DNMT3B gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 15 curated pathogenic missense variants (we use a threshold of 10). The gene has 33 curated benign missense variants. Gene score misZ: 1.5 (below the threshold of 3.09). Trascript score misZ: 3.3234 (above the threshold of 3.09). GenCC associations: The gene is linked to immunodeficiency-centromeric instability-facial anomalies syndrome, immunodeficiency-centromeric instability-facial anomalies syndrome 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.967

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DNMT3B	NM_006892.4	c.1987G>T	p.Gly663Cys	missense_variant	Exon 18 of 23	ENST00000328111.6	NP_008823.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DNMT3B	ENST00000328111.6	c.1987G>T	p.Gly663Cys	missense_variant	Exon 18 of 23	1	NM_006892.4	ENSP00000328547.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D;.;.;.;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D
M_CAP	Pathogenic	0.56	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	H;.;.;.;.;.
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-8.3	D;D;D;D;D;D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0010	D;D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D
Polyphen		1.0	D;D;D;.;.;D
Vest4		0.75
MutPred		0.88		Gain of methylation at K662 (P = 0.0149);.;.;.;.;.;
MVP		0.99
MPC		1.9
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs121908942; hg19: chr20-31388722;