rs121913593

chr1-161306110-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP3 PP5

The NM_000530.8(MPZ):c.643C>T(p.Gln215Ter) variant causes a stop gained, splice region change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars). Synonymous variant affecting the same amino acid position (i.e. Q215Q) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MPZ NM_000530.8 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9995
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.47

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 Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 17 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 1-161306110-G-A is Pathogenic according to our data. Variant chr1-161306110-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 14178.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr1-161306110-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MPZ	NM_000530.8	c.643C>T	p.Gln215Ter	stop_gained, splice_region_variant	5/6	ENST00000533357.5
MPZ	NM_001315491.2	c.643C>T	p.Gln215Ter	stop_gained, splice_region_variant	5/6
MPZ	XM_017001321.3	c.673C>T	p.Gln225Ter	stop_gained, splice_region_variant	5/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MPZ	ENST00000533357.5	c.643C>T	p.Gln215Ter	stop_gained, splice_region_variant	5/6	1	NM_000530.8	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Neuropathy, congenital hypomyelinating, 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Sep 01, 1996

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.50
Cadd	Pathogenic	62
Dann	Uncertain	1.0
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.94	D
MutationTaster	Benign	1.0	A;A;A;A
Vest4		0.93
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.96
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.99		Position offset: 2
DS_DL_spliceai		0.61		Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs121913593; hg19: chr1-161275900;