rs753107323

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM1

The NM_000530.8(MPZ):c.547T>C(p.Trp183Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000266 in 1,614,074 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000028 ( 0 hom. )

Consequence

MPZ
NM_000530.8 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 3.82

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]

MPZ links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM1

In a chain Myelin protein P0 (size 218) in uniprot entity MYP0_HUMAN there are 266 pathogenic changes around while only 9 benign (97%) in NM_000530.8

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
MPZ	NM_000530.8 linkuse as main transcript	c.547T>C	p.Trp183Arg	missense_variant	4/6	ENST00000533357.5
MPZ	NM_001315491.2 linkuse as main transcript	c.547T>C	p.Trp183Arg	missense_variant	4/6
MPZ	XM_017001321.3 linkuse as main transcript	c.577T>C	p.Trp193Arg	missense_variant	4/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MPZ	ENST00000533357.5 linkuse as main transcript	c.547T>C	p.Trp183Arg	missense_variant	4/6	1	NM_000530.8	P1	P25189-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152180

Hom.:

Cov.:

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

250806

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135650

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000265

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000280

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

727248

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:

0.0000351

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Charcot-Marie-Tooth disease

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Molecular Genetics Laboratory, London Health Sciences Centre

- -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 24, 2022

The p.W183R variant (also known as c.547T>C), located in coding exon 4 of the MPZ gene, results from a T to C substitution at nucleotide position 547. The tryptophan at codon 183 is replaced by arginine, an amino acid with dissimilar properties. This variant was identified in one allele in a Charcot-Marie Tooth cohort (Volodarsky M et al. J Med Genet, 2021 04;58:284-288). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Mayo Clinic Laboratories, Mayo Clinic

Feb 25, 2021

- -

Charcot-Marie-Tooth disease, type I

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 18, 2024

This sequence change replaces tryptophan, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 183 of the MPZ protein (p.Trp183Arg). This variant is present in population databases (rs753107323, gnomAD 0.003%). This missense change has been observed in individual(s) with clinical features of Charcot-Marie-Tooth disease (PMID: 32376792). ClinVar contains an entry for this variant (Variation ID: 581905). 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 not expected to disrupt MPZ protein function with a negative 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

Uncertain

0.46

BayesDel_addAF

Uncertain

0.068

BayesDel_noAF

Uncertain

-0.080

Cadd

Pathogenic

Dann

Uncertain

0.99

DEOGEN2

Benign

0.098

Eigen

Benign

-0.22

Eigen_PC

Benign

-0.043

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.63

M_CAP

Benign

0.054

MetaRNN

Uncertain

0.70

MetaSVM

Benign

-0.85

MutationAssessor

Benign

0.90

MutationTaster

Benign

0.99

D;D;D;D

PrimateAI

Uncertain

0.73

PROVEAN

Benign

0.61

REVEL

Uncertain

0.41

Sift

Benign

0.047

Sift4G

Benign

0.57

Polyphen

0.0030

Vest4

0.84

MutPred

0.69

Gain of helix (P = 0.0425);

MVP

0.86

MPC

2.0

ClinPred

0.88

GERP RS

3.9

Varity_R

0.21

gMVP

0.66

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over