rs1193634362

Variant names:

• chr11-68929243-T-C
• rs1193634362
• NM_002180.3:c.1121T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_002180.3(IGHMBP2):​c.1121T>C​(p.Ile374Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,216 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. I374V) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: IGHMBP2 NM_002180.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 7.69
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_002180.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.969
• PP5: Variant 11-68929243-T-C is Pathogenic according to our data. Variant chr11-68929243-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 433161.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IGHMBP2	NM_002180.3	c.1121T>C	p.Ile374Thr	missense_variant	Exon 8 of 15	ENST00000255078.8	NP_002171.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IGHMBP2	ENST00000255078.8	c.1121T>C	p.Ile374Thr	missense_variant	Exon 8 of 15	1	NM_002180.3	ENSP00000255078.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152216 Hom.: 0 Cov.: 32

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 Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152216 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74370

African (AFR) AF: 0.00 AC: 0 AN: 41464

American (AMR) AF: 0.00 AC: 0 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

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: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

Apr 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 374 of the IGHMBP2 protein (p.Ile374Thr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of autosomal recessive distal hereditary motor neuropathy (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 433161). 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. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

not specified Uncertain:1

Jan 05, 2017

Molecular Diagnostics Lab, Nemours Children's Health, Delaware

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Charcot-Marie-Tooth disease Uncertain:1

Aug 14, 2019

Genesis Genome Database

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: research

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.0	H
PhyloP100		7.7
PrimateAI	Uncertain	0.54	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0030	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.74		Loss of stability (P = 0.0213);
MVP		0.99
MPC		0.83
ClinPred		0.99	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.88
gMVP		0.88
Mutation Taster		=44/56	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

Other links and lift over

dbSNP: rs1193634362; hg19: chr11-68696711;