rs121913590

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_000530.8(MPZ):​c.292C>T​(p.Arg98Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,782 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R98L) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 29)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MPZ
NM_000530.8 missense

Scores

13
5
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 2.04
Variant links:
Genes affected
MPZ (HGNC:7225): (myelin protein zero) This gene is specifically expressed in Schwann cells of the peripheral nervous system and encodes a type I transmembrane glycoprotein that is a major structural protein of the peripheral myelin sheath. The encoded protein contains a large hydrophobic extracellular domain and a smaller basic intracellular domain, which are essential for the formation and stabilization of the multilamellar structure of the compact myelin. Mutations in this gene are associated with autosomal dominant form of Charcot-Marie-Tooth disease type 1 (CMT1B) and other polyneuropathies, such as Dejerine-Sottas syndrome (DSS) and congenital hypomyelinating neuropathy (CHN). A recent study showed that two isoforms are produced from the same mRNA by use of alternative in-frame translation termination codons via a stop codon readthrough mechanism. [provided by RefSeq, Oct 2015]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PM1
In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000530.8
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-161306863-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 14176.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.991
PP5
Variant 1-161306864-G-A is Pathogenic according to our data. Variant chr1-161306864-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 14175.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr1-161306864-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MPZNM_000530.8 linkc.292C>T p.Arg98Cys missense_variant Exon 3 of 6 ENST00000533357.5 NP_000521.2 P25189-1
MPZNM_001315491.2 linkc.292C>T p.Arg98Cys missense_variant Exon 3 of 6 NP_001302420.1 P25189A0A5F9ZI26
MPZXM_017001321.3 linkc.322C>T p.Arg108Cys missense_variant Exon 3 of 6 XP_016856810.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MPZENST00000533357.5 linkc.292C>T p.Arg98Cys missense_variant Exon 3 of 6 1 NM_000530.8 ENSP00000432943.1 P25189-1

Frequencies

GnomAD3 genomes
AF:
0.00000658
AC:
1
AN:
151976
Hom.:
0
Cov.:
29
show subpopulations
Gnomad AFR
AF:
0.0000242
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
GnomAD4 exome
AF:
0.00000137
AC:
2
AN:
1461806
Hom.:
0
Cov.:
34
AF XY:
0.00
AC XY:
0
AN XY:
727204
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000180
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
AF:
0.00000658
AC:
1
AN:
151976
Hom.:
0
Cov.:
29
AF XY:
0.0000135
AC XY:
1
AN XY:
74232
show subpopulations
Gnomad4 AFR
AF:
0.0000242
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:
0.00
Gnomad4 OTH
AF:
0.00

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Charcot-Marie-Tooth disease type 1B Pathogenic:4
Mar 01, 1996
OMIM
Significance: Pathogenic
Review Status: no assertion criteria provided
Collection Method: literature only

- -

Nov 06, 2013
Athena Diagnostics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jun 05, 2022
Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

ACMG classification criteria: PS3 supporting, PS4 strong, PM2 moderated, PM5 moderated, PM6 strong, PP3 supporting -

May 21, 2020
Baylor Genetics
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -

not provided Pathogenic:2
Feb 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

MPZ: PS2, PM1, PM2, PM5, PS3:Supporting -

Jun 06, 2022
GeneDx
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Published functional studies demonstrate a damaging effect; R98C results in reduced transport of the MPZ protein to the plasma membrane (Lee et al., 2010; Saporta et al., 2012).; Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are often considered pathogenic (HGMD); This variant is associated with the following publications: (PMID: 12477701, 23250879, 9168174, 9187667, 20461396, 19293842, 8816708, 8797476, 17172621, 10093067, 8644725, 21840889, 28704293, 29687021, 15050444, 10207934, 31211173, 31827005, 33825325, 26310628, 24077912, 22689911) -

Charcot-Marie-Tooth disease, type I Pathogenic:1
Sep 14, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 98 of the MPZ protein (p.Arg98Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with Charcot-Marie-Tooth disease and Dejerine-Sottas syndrome (PMID: 8644725, 8797476, 9168174, 20461396, 21840889). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 14175). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt MPZ protein function with a positive predictive value of 80%. Experimental studies have shown that this missense change affects MPZ function (PMID: 20461396, 22689911). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.99
BayesDel_addAF
Pathogenic
0.36
D
BayesDel_noAF
Pathogenic
0.28
CADD
Pathogenic
34
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.82
D
Eigen
Pathogenic
0.74
Eigen_PC
Uncertain
0.64
FATHMM_MKL
Uncertain
0.81
D
LIST_S2
Uncertain
0.92
D
M_CAP
Pathogenic
0.29
D
MetaRNN
Pathogenic
0.99
D
MetaSVM
Uncertain
0.17
D
MutationAssessor
Pathogenic
3.6
H
PrimateAI
Uncertain
0.75
T
PROVEAN
Pathogenic
-7.3
D
REVEL
Pathogenic
0.77
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0
D
Polyphen
1.0
D
Vest4
0.97
MutPred
0.94
Loss of catalytic residue at R98 (P = 0.0395);
MVP
0.98
MPC
1.8
ClinPred
1.0
D
GERP RS
3.7
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.95
gMVP
1.0

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.010
Details are displayed if max score is > 0.2

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.

Other links and lift over

dbSNP: rs121913590; hg19: chr1-161276654; COSMIC: COSV60668117; COSMIC: COSV60668117; API