rs876661217

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_002180.3(IGHMBP2):c.1148C>T(p.Ala383Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000508 in 1,613,682 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A383A) has been classified as Benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000055 ( 0 hom. )

Consequence

IGHMBP2
NM_002180.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 5.87

Variant links:

Genes affected

IGHMBP2 (HGNC:5542): (immunoglobulin mu DNA binding protein 2) This gene encodes a helicase superfamily member that binds a specific DNA sequence from the immunoglobulin mu chain switch region. Mutations in this gene lead to spinal muscle atrophy with respiratory distress type 1. [provided by RefSeq, Jul 2008]

IGHMBP2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_002180.3

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IGHMBP2	NM_002180.3 linkuse as main transcript	c.1148C>T	p.Ala383Val	missense_variant	8/15	ENST00000255078.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IGHMBP2	ENST00000255078.8 linkuse as main transcript	c.1148C>T	p.Ala383Val	missense_variant	8/15	1	NM_002180.3	P1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251052

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135748

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:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000547

AC:

AN:

1461508

Hom.:

Cov.:

AF XY:

0.0000495

AC XY:

AN XY:

727074

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000656

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74336

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000113

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jan 20, 2016	The c.1148 C>T variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Multiple in-silico splice prediction models predict that c.1148 C>T may create a cryptic splice donor site in exon 8 which may supplant the natural donor site and lead to abnormal splicing. However, in the absence of RNA/functional studies, the actual effect of this sequence change in this individual is unknown. If c.1148 C>T does not alter splicing, it will result in the A383V missense substitution, which is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved in mammals, and in silico analysis predicts this variant is probably damaging to the protein structure/function. Additionally, missense variants in nearby residues (V373G, E382K, W386R) have been reported in the Human Gene Mutation Database in association with IGHMBP2-related disorders (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Nov 14, 2019	- -

Autosomal recessive distal spinal muscular atrophy 1;C4015349:Charcot-Marie-Tooth disease axonal type 2S

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 08, 2022

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 383 of the IGHMBP2 protein (p.Ala383Val). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with IGHMBP2-related conditions. ClinVar contains an entry for this variant (Variation ID: 234786). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt IGHMBP2 protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 20, 2021

The p.A383V variant (also known as c.1148C>T), located in coding exon 8 of the IGHMBP2 gene, results from a C to T substitution at nucleotide position 1148. The alanine at codon 383 is replaced by valine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Uncertain

0.11

BayesDel_noAF

Uncertain

-0.010

Cadd

Pathogenic

Dann

Pathogenic

1.0

DEOGEN2

Uncertain

0.65

Eigen

Uncertain

0.46

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.97

M_CAP

Benign

0.067

MetaRNN

Pathogenic

0.83

MetaSVM

Uncertain

0.10

MutationAssessor

Benign

1.0

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.55

PROVEAN

Uncertain

-3.0

REVEL

Uncertain

0.62

Sift

Benign

0.049

Sift4G

Benign

0.27

Polyphen

0.80

Vest4

0.78

MutPred

0.62

Gain of helix (P = 0.2294);

MVP

0.90

MPC

0.63

ClinPred

0.91

GERP RS

5.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.1

Varity_R

0.55

gMVP

0.51

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.62

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.62

Position offset: -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