rs1483165002

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_002180.3(IGHMBP2):​c.1730T>C​(p.Leu577Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,614,016 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L577R) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

IGHMBP2
NM_002180.3 missense

Scores

12
6
1

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:3

Conservation

PhyloP100: 7.57

Publications

7 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 Gene-Disease associations (from GenCC):
  • autosomal recessive distal spinal muscular atrophy 1
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)
  • Charcot-Marie-Tooth disease axonal type 2S
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • hereditary peripheral neuropathy
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_002180.3
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr11-68935396-T-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1066593.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.99
PP5
Variant 11-68935396-T-C is Pathogenic according to our data. Variant chr11-68935396-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 522868.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
IGHMBP2NM_002180.3 linkc.1730T>C p.Leu577Pro missense_variant Exon 12 of 15 ENST00000255078.8 NP_002171.2 P38935

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
IGHMBP2ENST00000255078.8 linkc.1730T>C p.Leu577Pro missense_variant Exon 12 of 15 1 NM_002180.3 ENSP00000255078.4 P38935

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152266
Hom.:
0
Cov.:
34
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251442
AF XY:
0.00
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000879
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461750
Hom.:
0
Cov.:
32
AF XY:
0.00000138
AC XY:
1
AN XY:
727178
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53288
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
8.99e-7
AC:
1
AN:
1112002
Other (OTH)
AF:
0.00
AC:
0
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.525
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
AF:
0.00000657
AC:
1
AN:
152266
Hom.:
0
Cov.:
34
AF XY:
0.00
AC XY:
0
AN XY:
74396
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000241
AC:
1
AN:
41476
American (AMR)
AF:
0.00
AC:
0
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4838
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:
0.00
AC:
0
AN:
68040
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), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000113

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:2Uncertain:3
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Inborn genetic diseases Pathogenic:1
Dec 11, 2023
Ambry Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.1730T>C (p.L577P) alteration is located in coding exon 12 of the IGHMBP2 gene. This alteration results from a T to C substitution at nucleotide position 1730, causing the leucine (L) at amino acid position 577 to be replaced by a proline (P). This allele was reported in one heterozygous individual in population-based cohorts in the Genome Aggregation Database (gnomAD). This has been reported as a compound heterozygous finding in multiple unrelated children with IGHMBP2-related neuropathy (Grohmann, 2003; Maystadt, 2004; Cassini, 2019). Another alteration at the same codon, c.1730T>G (p.L577R), has been detected as a compound heterozygous finding in a 2 month old Chinese male with spinal muscular atrophy with respiratory distress 1 (SMARD1) (Han, 2015). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -

Autosomal recessive distal spinal muscular atrophy 1;C4015349:Charcot-Marie-Tooth disease axonal type 2S Pathogenic:1
Mar 09, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 577 of the IGHMBP2 protein (p.Leu577Pro). For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Leu577 amino acid residue in IGHMBP2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 25280635; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on IGHMBP2 protein function. ClinVar contains an entry for this variant (Variation ID: 522868). This missense change has been observed in individuals with Charcot-Marie-Tooth disease and/or spinal muscular atrophy with respiratory distress (PMID: 14681881, 15108294, 30598237, 31020813). This variant is present in population databases (no rsID available, gnomAD 0.0009%). -

Neuronopathy, distal hereditary motor, autosomal dominant Uncertain:1
-
Inherited Neuropathy Consortium
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:literature only

- -

not provided Uncertain:1
Sep 11, 2019
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Charcot-Marie-Tooth disease axonal type 2S Uncertain:1
Feb 07, 2017
Undiagnosed Diseases Network, NIH
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.1730T>C variant has been observed in multiple, unrelated, affected individuals with Charcot Marie-Tooth disease 2 (Grohmann K, Varon R, Stolz P, et al. 2003). In addition, multiple lines of computational evidence support a deleterious effect of the p.Leu577Pro variant on the gene or gene product. This individual has been reported in PMID: 31020813. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.97
BayesDel_addAF
Pathogenic
0.52
D
BayesDel_noAF
Pathogenic
0.51
CADD
Pathogenic
29
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.89
D
Eigen
Uncertain
0.68
Eigen_PC
Uncertain
0.53
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
0.98
D
M_CAP
Pathogenic
0.47
D
MetaRNN
Pathogenic
0.99
D
MetaSVM
Pathogenic
0.96
D
MutationAssessor
Pathogenic
3.4
M
PhyloP100
7.6
PrimateAI
Uncertain
0.78
T
PROVEAN
Pathogenic
-5.2
D
REVEL
Pathogenic
0.88
Sift
Uncertain
0.0020
D
Sift4G
Uncertain
0.0040
D
Polyphen
1.0
D
Vest4
0.99
MutPred
0.92
Gain of disorder (P = 0.0177);
MVP
0.99
MPC
0.97
ClinPred
0.98
D
GERP RS
3.8
Varity_R
0.99
gMVP
0.98
Mutation Taster
=6/94
disease causing

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: rs1483165002; hg19: chr11-68702864; API