3-129431556-A-T

Position:

chr3-129431556-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PVS1_ModeratePM2PP5

The NM_001276270.2(MBD4):c.1670T>A(p.Leu557Ter) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000539 in 1,612,848 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000055 ( 0 hom. )

Consequence

MBD4
NM_001276270.2 stop_gained

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1O:1

Conservation

PhyloP100: 7.66

Variant links:

Genes affected

MBD4 (HGNC:6919): (methyl-CpG binding domain 4, DNA glycosylase) The protein encoded by this gene is a member of a family of nuclear proteins related by the presence of a methyl-CpG binding domain (MBD). These proteins are capable of binding specifically to methylated DNA, and some members can also repress transcription from methylated gene promoters. This protein contains an MBD domain at the N-terminus that functions both in binding to methylated DNA and in protein interactions and a C-terminal mismatch-specific glycosylase domain that is involved in DNA repair. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Jan 2013]

MBD4 links:

IFT122 (HGNC:13556): (intraflagellar transport 122) This gene encodes a member of the WD repeat protein family. WD repeats are minimally conserved regions of approximately 40 amino acids typically bracketed by gly-his and trp-asp (GH-WD), which may facilitate formation of heterotrimeric or multiprotein complexes. Members of this family are involved in a variety of cellular processes, including cell cycle progression, signal transduction, apoptosis, and gene regulation. This cytoplasmic protein contains seven WD repeats and an AF-2 domain which function by recruiting coregulatory molecules and in transcriptional activation. Mutations in this gene cause cranioectodermal dysplasia-1. A related pseudogene is located on chromosome 3. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2013]

IFT122 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0319 CDS is truncated, and there are 1 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 3-129431556-A-T is Pathogenic according to our data. Variant chr3-129431556-A-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1700254.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MBD4	NM_001276270.2 linkuse as main transcript	c.1670T>A	p.Leu557Ter	stop_gained	8/8	ENST00000429544.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MBD4	ENST00000429544.7 linkuse as main transcript	c.1670T>A	p.Leu557Ter	stop_gained	8/8	1	NM_001276270.2	A2	O95243-2

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000319

AC:

AN:

250988

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135698

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000704

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000555

AC:

AN:

1460610

Hom.:

Cov.:

AF XY:

0.0000427

AC XY:

AN XY:

726658

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000675

Gnomad4 OTH exome

AF:

0.0000828

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152238

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74378

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000113

Hom.:

Bravo

AF:

0.0000302

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.0000576

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Tumor predisposition syndrome 2

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Jul 17, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with tumour predisposition syndrome 2 (MIM#619975). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0205 - Variant is predicted to result in a truncated protein (premature termination codon is NOT located at least 54 nucleotides upstream of the final exon-exon junction) with less than 1/3 of the protein sequence affected. (SP) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2 - 8 heterozygotes, 0 homozygotes). (SP) 0601 - Variant is located in the well-established glycosylase domain (PMID: 30049810; PMID: PMID: 32239153). (I) 0704 - Another variant comparable to the one identified in this case has limited previous evidence for pathogenicity. PMID: 30049810 report a male with colonic polyposis and AML homozygous for the MBD4 c.1699_1701del (p.His567del) variant. This variant is predicted to result in an in-frame deletion in the glycosylase domain and glycosylase assays demonstrated that it led to catalytically inactive MBD4. PMID 32239153 identified a germline heterozygous MBD4 c.1706G>A; p.(Trp569) variant in two unrelated patients with uveal melanoma. Testing on tumour tissue was undertaken in one of these patients and demonstrated somatic loss of the wild-type allele due to monosomy 3. In vitro glycosylase assay confirmed that this variant resulted in catalytically inactive protein. (SP) 0803 - This variant has moderate previous evidence of pathogenicity in at least three unrelated individuals. PMID 35460607 identified this variant compound heterozygous with MBD4 c.939dup (p.Glu314Argfs13) in a female with colonic polyposis and uveal melanoma. Her deceased sibling with a history of polyposis and AML could not be genotyped. Griffin et al. 2021 (ASH poster abstract) report this variant in trans with MBD4 c.1291C>T (p.Arg431*) in a female wtih AML and colorectal polyposis. This individual's deceased sibling with a history of AML, colorectal cancer and lymphoma could not be genotyped. PMID 30714079 identified this variant as heterozygous in the germline of an individual with uveal melanoma, with hemizygosity for this variant confirmed in the tumour in association with high tumour mutational burden. (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1101 - Very strong and specific phenotype match for this individual. (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, no assertion criteria provided	literature only	OMIM	Aug 08, 2022	- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 29, 2024

This sequence change creates a premature translational stop signal (p.Leu563*) in the MBD4 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 18 amino acid(s) of the MBD4 protein. This variant is present in population databases (rs200758755, gnomAD 0.008%). This premature translational stop signal has been observed in individual(s) with clinical features of MBD4-associated neoplasia syndrome (PMID: 30049810, 30714079, 32239153, 35460607). This variant is also known as Leu563Ter. ClinVar contains an entry for this variant (Variation ID: 1700254). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Melanoma, uveal, susceptibility to, 1

Other:1

risk factor, no assertion criteria provided

literature only

OMIM

Aug 08, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.63

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

0.89

Eigen_PC

Pathogenic

0.76

FATHMM_MKL

Pathogenic

0.99

MutationTaster

Benign

1.0

D;D;D;D

Vest4

0.62

GERP RS

5.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over