20-32800271-C-T

Variant names:

• chr20-32800271-C-T
• rs17123655
• NM_006892.4:c.1878C>T

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BA1

The NM_006892.4(DNMT3B):​c.1878C>T​(p.Asn626Asn) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0044 in 1,614,140 control chromosomes in the GnomAD database, including 263 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

• Frequency:
  • Genomes: 𝑓 0.023 (127 hom., cov: 32)
  • Exomes 𝑓: 0.0025 (136 hom.)
• Consequence: DNMT3B NM_006892.4 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: -1.18

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 Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.59).
• BP6: Variant 20-32800271-C-T is Benign according to our data. Variant chr20-32800271-C-T is described in ClinVar as [Benign]. Clinvar id is 338178.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-1.18 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0754 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DNMT3B	NM_006892.4	c.1878C>T	p.Asn626Asn	synonymous_variant	Exon 17 of 23	ENST00000328111.6	NP_008823.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DNMT3B	ENST00000328111.6	c.1878C>T	p.Asn626Asn	synonymous_variant	Exon 17 of 23	1	NM_006892.4	ENSP00000328547.2

Frequencies

GnomAD3 genomes AF: 0.0228 AC: 3469 AN: 152132 Hom.: 128 Cov.: 32

Gnomad AFR AF: 0.0775

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0111

Gnomad ASJ AF: 0.00288

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000621

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.0127

Gnomad NFE AF: 0.000470

Gnomad OTH AF: 0.0186

GnomAD3 exomes AF: 0.00633 AC: 1593 AN: 251490 Hom.: 56 AF XY: 0.00451 AC XY: 613 AN XY: 135922

Gnomad AFR exome AF: 0.0818

Gnomad AMR exome AF: 0.00457

Gnomad ASJ exome AF: 0.00198

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000492

Gnomad OTH exome AF: 0.00309

GnomAD4 exome AF: 0.00248 AC: 3620 AN: 1461890 Hom.: 136 Cov.: 35 AF XY: 0.00216 AC XY: 1570 AN XY: 727246

Gnomad4 AFR exome AF: 0.0802

Gnomad4 AMR exome AF: 0.00483

Gnomad4 ASJ exome AF: 0.00191

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000237

Gnomad4 OTH exome AF: 0.00556

GnomAD4 genome AF: 0.0229 AC: 3480 AN: 152250 Hom.: 127 Cov.: 32 AF XY: 0.0219 AC XY: 1627 AN XY: 74430

Gnomad4 AFR AF: 0.0776

Gnomad4 AMR AF: 0.0110

Gnomad4 ASJ AF: 0.00288

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000622

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000470

Gnomad4 OTH AF: 0.0184

Alfa AF: 0.0122 Hom.: 50

Bravo AF: 0.0257

Asia WGS AF: 0.00722 AC: 25 AN: 3478

EpiCase AF: 0.000327

EpiControl AF: 0.000711

ClinVar

Significance: Benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Immunodeficiency-centromeric instability-facial anomalies syndrome 1 Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

not provided Benign:1

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

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

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: 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	-0.59
CADD	Benign	8.8
DANN	Benign	0.74

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.20		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.20		Position offset: 3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs17123655; hg19: chr20-31388077;