rs1334447515

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_002180.3(IGHMBP2):​c.46C>G​(p.Leu16Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000715 in 1,398,962 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. L16L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 35)
Exomes 𝑓: 7.1e-7 ( 0 hom. )
Failed GnomAD Quality Control

Consequence

IGHMBP2
NM_002180.3 missense

Scores

7
9
3

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 2.49

Publications

2 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]
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]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
IGHMBP2NM_002180.3 linkc.46C>G p.Leu16Val missense_variant Exon 1 of 15 ENST00000255078.8 NP_002171.2 P38935
MRPL21NM_181514.2 linkc.-188G>C upstream_gene_variant ENST00000362034.7 NP_852615.1 Q7Z2W9-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
IGHMBP2ENST00000255078.8 linkc.46C>G p.Leu16Val missense_variant Exon 1 of 15 1 NM_002180.3 ENSP00000255078.4 P38935
MRPL21ENST00000362034.7 linkc.-188G>C upstream_gene_variant 1 NM_181514.2 ENSP00000354580.2 Q7Z2W9-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152210
Hom.:
0
Cov.:
35
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
7.15e-7
AC:
1
AN:
1398962
Hom.:
0
Cov.:
44
AF XY:
0.00000145
AC XY:
1
AN XY:
690246
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
31602
American (AMR)
AF:
0.00
AC:
0
AN:
35730
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25164
East Asian (EAS)
AF:
0.00
AC:
0
AN:
35762
South Asian (SAS)
AF:
0.00
AC:
0
AN:
79600
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
48198
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5678
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1079214
Other (OTH)
AF:
0.0000172
AC:
1
AN:
58014
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Data not reliable, filtered out with message: AS_VQSR
AF:
0.00000657
AC:
1
AN:
152210
Hom.:
0
Cov.:
35
AF XY:
0.0000134
AC XY:
1
AN XY:
74356
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41452
American (AMR)
AF:
0.00
AC:
0
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5170
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68042
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.275
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.0000540
Hom.:
0
Bravo
AF:
0.00000756

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Autosomal recessive distal spinal muscular atrophy 1;C4015349:Charcot-Marie-Tooth disease axonal type 2S Uncertain:1
Nov 14, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 16 of the IGHMBP2 protein (p.Leu16Val). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with IGHMBP2-related conditions. 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 expected to disrupt IGHMBP2 protein function with a positive predictive value of 80%. 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
0.26
BayesDel_addAF
Pathogenic
0.25
D
BayesDel_noAF
Uncertain
0.11
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.65
D;.
Eigen
Uncertain
0.67
Eigen_PC
Uncertain
0.56
FATHMM_MKL
Benign
0.28
N
LIST_S2
Uncertain
0.86
D;T
M_CAP
Pathogenic
0.80
D
MetaRNN
Uncertain
0.70
D;D
MetaSVM
Pathogenic
0.97
D
MutationAssessor
Pathogenic
3.2
M;.
PhyloP100
2.5
PrimateAI
Uncertain
0.74
T
PROVEAN
Uncertain
-2.4
N;D
REVEL
Pathogenic
0.70
Sift
Pathogenic
0.0
D;D
Sift4G
Pathogenic
0.0
D;D
Polyphen
1.0
D;.
Vest4
0.42
MutPred
0.53
Gain of methylation at K12 (P = 0.1235);Gain of methylation at K12 (P = 0.1235);
MVP
0.97
MPC
0.74
ClinPred
0.99
D
GERP RS
4.2
PromoterAI
0.014
Neutral
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.77
gMVP
0.65
Mutation Taster
=53/47
polymorphism

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

Other links and lift over

dbSNP: rs1334447515; hg19: chr11-68671466; API