2-148462624-A-G

Variant names:

• chr2-148462624-A-G
• rs796958008
• NM_001378120.1:c.156A>G

Variant summary

Our verdict is Benign. Variant got -11 ACMG points: 2P and 13B. PM2 BP4_Strong BP6_Very_Strong BP7

The NM_001378120.1(MBD5):​c.156A>G​(p.Thr52Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,244 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 Likely benign (★★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 32)
• Consequence: MBD5 NM_001378120.1 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: 0.766

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]

ACMG classification

Verdict is Benign. Variant got -11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.5).
• BP6: Variant 2-148462624-A-G is Benign according to our data. Variant chr2-148462624-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 468770.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.766 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MBD5	NM_001378120.1	c.156A>G	p.Thr52Thr	synonymous_variant	Exon 6 of 14	ENST00000642680.2	NP_001365049.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MBD5	ENST00000642680.2	c.156A>G	p.Thr52Thr	synonymous_variant	Exon 6 of 14		NM_001378120.1	ENSP00000493871.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152244 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74432

Gnomad4 AFR AF: 0.0000481

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Jul 06, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MBD5 c.156A>G alters a non-conserved nucleotide resulting in a synonymous change. 3/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251146 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.156A>G in individuals affected with MBD5 Associated Neurodevelopmental Disorder and no experimental evidence demonstrating its impact on protein function have been reported. One submitter has cited clinical-significance assessments for this variant to ClinVar after 2014 and has classified the variant as benign. Based on the evidence outlined above, the variant was classified as likely benign. -

Intellectual disability, autosomal dominant 1 Benign:1

Aug 23, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

MBD5-related disorder Benign:1

Feb 21, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.50
CADD	Benign	13
DANN	Benign	0.69

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.13		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: rs796958008; hg19: chr2-149220193;