11-68903956-G-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM1BP4

The NM_002180.3(IGHMBP2):c.4G>T(p.Ala2Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000894 in 1,566,356 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A2T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 35)

Exomes 𝑓: 0.0000028 ( 0 hom. )

Consequence

IGHMBP2
NM_002180.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 2.80

Publications

1 publications found

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:

MRPL21 (HGNC:14479): (mitochondrial ribosomal protein L21) Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 39S subunit protein. Multiple transcript variants encoding different isoforms were identified through sequence analysis although some may be subject to nonsense-mediated decay (NMD). [provided by RefSeq, Jul 2008]

MRPL21 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1

In a modified_residue N-acetylalanine (size 0) in uniprot entity SMBP2_HUMAN

BP4

Computational evidence support a benign effect (MetaRNN=0.34026277).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IGHMBP2	NM_002180.3 link	c.4G>T	p.Ala2Ser	missense_variant	Exon 1 of 15	ENST00000255078.8	NP_002171.2	P38935
MRPL21	NM_181514.2 link	c.-146C>A		upstream_gene_variant		ENST00000362034.7	NP_852615.1	Q7Z2W9-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IGHMBP2	ENST00000255078.8 link	c.4G>T	p.Ala2Ser	missense_variant	Exon 1 of 15	1	NM_002180.3	ENSP00000255078.4		P38935
MRPL21	ENST00000362034.7 link	c.-146C>A		upstream_gene_variant		1	NM_181514.2	ENSP00000354580.2		Q7Z2W9-1

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152246

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000217

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000583

AC:

AN:

171622

AF XY:

0.0000108

show subpopulations

Gnomad AFR exome

AF:

0.000104

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000283

AC:

AN:

1414110

Hom.:

Cov.:

AF XY:

0.00000429

AC XY:

AN XY:

699612

show subpopulations

African (AFR)

AF:

0.000124

AC:

AN:

32198

American (AMR)

AF:

0.00

AC:

AN:

36962

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25328

East Asian (EAS)

AF:

0.00

AC:

AN:

36860

South Asian (SAS)

AF:

0.00

AC:

AN:

81864

European-Finnish (FIN)

AF:

0.00

AC:

AN:

49020

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5692

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1087620

Other (OTH)

AF:

0.00

AC:

AN:

58566

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152246

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74382

show subpopulations

African (AFR)

AF:

0.000217

AC:

AN:

41472

American (AMR)

AF:

0.00

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.000288

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68042

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000604

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Mar 14, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.4G>T (p.A2S) alteration is located in exon 1 (coding exon 1) of the IGHMBP2 gene. This alteration results from a G to T substitution at nucleotide position 4, causing the alanine (A) at amino acid position 2 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

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

Uncertain:1

Aug 30, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces alanine with serine at codon 2 of the IGHMBP2 protein (p.Ala2Ser). The alanine residue is weakly conserved and there is a moderate physicochemical difference between alanine and serine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with IGHMBP2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.078

BayesDel_addAF

Benign

-0.054

BayesDel_noAF

Benign

-0.090

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.057

T;.

Eigen

Benign

-0.20

Eigen_PC

Benign

-0.10

FATHMM_MKL

Benign

0.18

LIST_S2

Benign

0.65

T;T

M_CAP

Pathogenic

0.41

MetaRNN

Benign

0.34

T;T

MetaSVM

Uncertain

0.045

MutationAssessor

Uncertain

2.3

M;.

PhyloP100

2.8

PrimateAI

Uncertain

0.72

PROVEAN

Benign

-0.31

N;N

REVEL

Benign

0.21

Sift

Benign

0.053

T;T

Sift4G

Benign

0.45

T;T

Polyphen

0.068

B;.

Vest4

0.23

MutPred

0.10

Gain of phosphorylation at A2 (P = 0.0273);Gain of phosphorylation at A2 (P = 0.0273);

MVP

0.91

MPC

0.18

ClinPred

0.61

GERP RS

3.4

PromoterAI

-0.068

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.6

Varity_R

0.079

gMVP

0.62

Mutation Taster

=93/7

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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11-68903956-G-T

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over