DNA Methyltransferase 3B

Alternative Names

  • DNMT3B
  • DNA (Cytosine-5-)-Methyltransferase 3 Beta
  • DNA Methyltransferase HsaIIIB
  • DNA MTase HsaIIIB
  • M.HsaIIIB
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OMIM Number

602900

NCBI Gene ID

1789

Uniprot ID

Q9UBC3

Length

46,972 bases

No. of Exons

24

No. of isoforms

8

Protein Name

DNA (Cytosine-5)-Methyltransferase 3B

Molecular Mass

95751 Da

Amino Acid Count

853

Genomic Location

chr20:32,762,384-32,809,355

Gene Map Locus
20q11.21

Description

DNMT3B encodes a DNA methyltransferase predicted to act in de novo methylation. DNA methylation is an epigenetic modification essential to mammalian development. It is associated with several key processes such as genomic imprinting, X-chromosome inactivation, repression of repetitive elements, aging and carcinogenesis. The DNMT3B gene has also been assumed to function as a transcriptional co-repressor with CBX4 and as a gene silencer.

Given the important role DNA methylation plays in mammalian cells, defects in the gene can have severe pathological consequences. Mutations in DNMT3B have been associated with Immunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 1 (ICF1).

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_006892.3:c.2308A>GLebanonNC_000020.11:g.32806215A>GLikely PathogenicImmunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 1NG_007290.1:g.48831A>G; NM_006892.3:c.2308A>G; NP_008823.1:p.Lys770Glu
NM_006892.4:c.2477G>ALebanonchr20:32807818Uncertain SignificancePathogenicImmunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 1NG_007290.1:g.50434G>A; NM_006892.4:c.2477G>A; NP_008823.1:p.Arg826His7569722541026466
NM_006892.4:c.2506G>ASaudi ArabiaNC_000020.11:g.32807847G>ALikely PathogenicPathogenicImmunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 1NG_007290.1:g.50463G>A; NM_006892.4:c.2506G>A; NP_008823.1:p.Val836Met8667924831324289

Other Reports

Saudi Arabia

Kaya et al. (2011) described 5 female ICF1 patients from Saudi Arabia. Four of the patients were from consanguineous families and most presented in infancy. The patients suffered from hypogammaglobulinemia and also showed dysmorphic features such as micrognathia, hypertelorism and low set ears.  Most patients also suffered from lower respiratory tract infections. One of the patients had pseudomonas meningitis while another had septicemia due to pseudomonas. Pauciarticular Juvenile Idiopathic Arthritis was noted in one patient. Cytogenetic studies were carried out on phytohemagglutinin stimulated lymphocyte cultures and juxtacentromeric heterochromatin instability was seen involving chromosomes 1 and 16 in all patients. This extended to chromosome 9 in 3 patients. Genetic analysis of the DNMT3B gene was carried out in 3 of the ICF1 patients. A novel homozygous c.2506G>A transition in the last exon of the gene, resulting in a p.V836M substitution, was discovered in patient 3. This mutation was not found in 100 ethnically-matched chromosomes. In silico analysis using PolyPhen, SIFT and PANTHER all predicted this mutation to have a damaging or deleterious effect on the protein.

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