dbSNP rs1060501153: MBD5:p.Asn767LeufsTer16 (chr2-148470238-CACTA-C) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate

The NM_001378120.1(MBD5):c.2299_2302delAACT(p.Asn767LeufsTer16) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Consequence

MBD5
NM_001378120.1 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 6.12

Variant links:

Genes affected

MBD5 (HGNC:20444): (methyl-CpG binding domain protein 5) This gene encodes a member of the methyl-CpG-binding domain (MBD) family. The MBD consists of about 70 residues and is the minimal region required for a methyl-CpG-binding protein binding specifically to methylated DNA. In addition to the MBD domain, this protein contains a PWWP domain (Pro-Trp-Trp-Pro motif), which consists of 100-150 amino acids and is found in numerous proteins that are involved in cell division, growth and differentiation. Mutations in this gene cause an autosomal dominant type of cognitive disability. The encoded protein interacts with the polycomb repressive complex PR-DUB which catalyzes the deubiquitination of a lysine residue of histone 2A. Haploinsufficiency of this gene is associated with a syndrome involving microcephaly, intellectual disabilities, severe speech impairment, and seizures. Alternatively spliced transcript variants have been found, but their full-length nature is not determined. [provided by RefSeq, Jul 2017]

MBD5 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-148470238-CACTA-C is Pathogenic according to our data. Variant chr2-148470238-CACTA-C is described in ClinVar as [Pathogenic]. Clinvar id is 406455.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MBD5	NM_001378120.1 link	c.2299_2302delAACT	p.Asn767LeufsTer16	frameshift_variant	Exon 8 of 14	ENST00000642680.2	NP_001365049.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MBD5	ENST00000642680.2 link	c.2299_2302delAACT	p.Asn767LeufsTer16	frameshift_variant	Exon 8 of 14		NM_001378120.1	ENSP00000493871.2		A0A2R8YDL9

Frequencies

GnomAD3 genomes

Cov.:

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Intellectual disability, autosomal dominant 1

Pathogenic:1

Oct 13, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

While this particular variant has not been reported in the literature, truncating variants in MBD5 are known to be pathogenic (PMID: 23422940). This sequence change deletes 4 nucleotide from exon 9 of the MBD5 mRNA (c.2299_2302delAACT), causing a frameshift at codon 767. This creates a premature translational stop signal (p.Asn767Leufs*16) and is expected to result in an absent or disrupted protein product. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing