rs121913608

Positions:

• chr1-161306789-C-A
• chr1-161306789-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000530.8(MPZ):​c.367G>T​(p.Gly123Cys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G123D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 29)
• Consequence: MPZ NM_000530.8 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 7.15

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a strand (size 8) in uniprot entity MYP0_HUMAN there are 18 pathogenic changes around while only 0 benign (100%) 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 chr1-161306788-C-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MPZ	NM_000530.8	c.367G>T	p.Gly123Cys	missense_variant	3/6	ENST00000533357.5	NP_000521.2
MPZ	NM_001315491.2	c.367G>T	p.Gly123Cys	missense_variant	3/6		NP_001302420.1
MPZ	XM_017001321.3	c.397G>T	p.Gly133Cys	missense_variant	3/6		XP_016856810.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MPZ	ENST00000533357.5	c.367G>T	p.Gly123Cys	missense_variant	3/6	1	NM_000530.8	ENSP00000432943	P1

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 29

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

Charcot-Marie-Tooth disease Uncertain:1

Uncertain significance, no assertion criteria provided

literature only

Inherited Neuropathy Consortium

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	H
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-8.5	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		1.0
MutPred		0.96		Loss of catalytic residue at G123 (P = 0.0652);
MVP		0.99
MPC		1.6
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.97
gMVP		0.99

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

Other links and lift over

dbSNP: rs121913608; hg19: chr1-161276579;