NM_000530.8:c.200G>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 7P and 1B. PM1PM2PM5PP2BP4

The NM_000530.8(MPZ):c.200G>T(p.Arg67Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,866 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R67H) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MPZ
NM_000530.8 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.608

Publications

2 publications found

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 Gene-Disease associations (from GenCC):

Charcot-Marie-Tooth disease
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
Charcot-Marie-Tooth disease type 1B
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Orphanet
neuropathy, congenital hypomyelinating, 2
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
autosomal dominant intermediate Charcot-Marie-Tooth disease with neuropathic pain
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Charcot-Marie-Tooth disease dominant intermediate D
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Charcot-Marie-Tooth disease type 2I
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Charcot-Marie-Tooth disease type 2J
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Charcot-Marie-Tooth disease type 3
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

MPZ links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 23 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 chr1-161307292-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 637325.Status of the report is criteria_provided_single_submitter, 1 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 84 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 0.98749 (below the threshold of 3.09). Trascript score misZ: 1.4782 (below the threshold of 3.09). GenCC associations: The gene is linked to Charcot-Marie-Tooth disease dominant intermediate D, Charcot-Marie-Tooth disease type 1B, autosomal dominant intermediate Charcot-Marie-Tooth disease with neuropathic pain, Charcot-Marie-Tooth disease type 2J, neuropathy, congenital hypomyelinating, 2, Charcot-Marie-Tooth disease type 2I, Charcot-Marie-Tooth disease type 3, Charcot-Marie-Tooth disease.

BP4

Computational evidence support a benign effect (MetaRNN=0.37252322).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MPZ	NM_000530.8 link	c.200G>T	p.Arg67Leu	missense_variant	Exon 2 of 6	ENST00000533357.5	NP_000521.2	P25189-1
MPZ	NM_001315491.2 link	c.200G>T	p.Arg67Leu	missense_variant	Exon 2 of 6		NP_001302420.1	P25189A0A5F9ZI26
MPZ	XM_017001321.3 link	c.230G>T	p.Arg77Leu	missense_variant	Exon 2 of 6		XP_016856810.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MPZ	ENST00000533357.5 link	c.200G>T	p.Arg67Leu	missense_variant	Exon 2 of 6	1	NM_000530.8	ENSP00000432943.1		P25189-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461866

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727234

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112006

Other (OTH)

AF:

0.00

AC:

AN:

60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 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

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.65

BayesDel_addAF

Uncertain

0.020

BayesDel_noAF

Benign

-0.21

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.31

Eigen

Benign

0.025

Eigen_PC

Benign

0.14

FATHMM_MKL

Benign

0.62

LIST_S2

Benign

0.82

M_CAP

Benign

0.017

MetaRNN

Benign

0.37

MetaSVM

Benign

-1.1

MutationAssessor

Benign

0.95

PhyloP100

0.61

PrimateAI

Uncertain

0.59

PROVEAN

Benign

-2.1

REVEL

Uncertain

0.30

Sift

Benign

0.077

Sift4G

Benign

0.10

Polyphen

0.74

Vest4

0.24

MutPred

0.58

Gain of catalytic residue at R67 (P = 0.0211);

MVP

0.82

MPC

0.68

ClinPred

0.70

GERP RS

5.2

PromoterAI

-0.010

Neutral

(source)

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.47

gMVP

0.96

Mutation Taster

=17/83

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over