rs879254038

Variant names:

• chr1-161306800-T-C
• rs879254038
• NM_000530.8:c.356A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP5

The NM_000530.8(MPZ):​c.356A>G​(p.Tyr119Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: MPZ NM_000530.8 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:7 U:2
• Conservation: PhyloP100: 0.620
• Publications: 6 publications found

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: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), 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

ACMG classification

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

• PM1: In a hotspot region, there are 15 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 24 uncertain in NM_000530.8
• PM2: Very rare variant in population databases, with high coverage
• 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.
• PP5: Variant 1-161306800-T-C is Pathogenic according to our data. Variant chr1-161306800-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 245997.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000530.8. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MPZ	NM_000530.8	MANE Select	c.356A>G	p.Tyr119Cys	missense	Exon 3 of 6	NP_000521.2	P25189-1
	MPZ	NM_001315491.2		c.356A>G	p.Tyr119Cys	missense	Exon 3 of 6	NP_001302420.1	A0A5F9ZI26

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MPZ	ENST00000533357.5	TSL:1 MANE Select	c.356A>G	p.Tyr119Cys	missense	Exon 3 of 6	ENSP00000432943.1	P25189-1
	MPZ	ENST00000463290.5	TSL:1	n.356A>G		non_coding_transcript_exon	Exon 3 of 7	ENSP00000431538.1	P25189-1
	MPZ	ENST00000672287.2		c.-233A>G		5_prime_UTR_premature_start_codon_gain	Exon 2 of 5	ENSP00000499818.2	E9PL80

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461872 Hom.: 0 Cov.: 34 AF XY: 0.00000413 AC XY: 3 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111992

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 29

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
4	-	-	not provided (4)
2	-	-	Charcot-Marie-Tooth disease type 1B (2)
-	1	-	Charcot-Marie-Tooth disease (1)
1	-	-	Charcot-Marie-Tooth disease, type I (1)
-	1	-	Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.63
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.60	D
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Benign	0.74	D
LIST_S2	Uncertain	0.91	D
M_CAP	Benign	0.040	D
MetaRNN	Uncertain	0.74	D
MetaSVM	Benign	-0.80	T
MutationAssessor	Uncertain	2.0	M
PhyloP100		0.62
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-3.1	D
REVEL	Uncertain	0.38
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.016	D
Polyphen		0.99	D
Vest4		0.68
MutPred		0.47		Loss of phosphorylation at Y119 (P = 0.0516)
MVP		0.92
MPC		1.3
ClinPred		0.98	D
GERP RS		4.8
Varity_R		0.67
gMVP		0.98
Mutation Taster		=5/95	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs879254038; hg19: chr1-161276590;