chr1-161306879-C-T

Variant names:

• chr1-161306879-C-T
• rs1553259691
• NM_000530.8:c.277G>A

Variant summary

Our verdict is Pathogenic. The variant received 21 ACMG points: 21P and 0B. PS1 PM1 PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_000530.8(MPZ):​c.277G>A​(p.Gly93Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G93A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 29)
• Consequence: MPZ NM_000530.8 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 3.55
• Publications: 0 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: Pathogenic. The variant received 21 ACMG points.

• PS1: Transcript NM_000530.8 (MPZ) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 14 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 19 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 chr1-161306878-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 411666.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.873
• PP5: Variant 1-161306879-C-T is Pathogenic according to our data. Variant chr1-161306879-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 1067479.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.277G>A	p.Gly93Arg	missense	Exon 3 of 6	NP_000521.2	P25189-1
	MPZ	NM_001315491.2		c.277G>A	p.Gly93Arg	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.277G>A	p.Gly93Arg	missense	Exon 3 of 6	ENSP00000432943.1	P25189-1
	MPZ	ENST00000463290.5	TSL:1	n.277G>A		non_coding_transcript_exon	Exon 3 of 7	ENSP00000431538.1	P25189-1
	MPZ	ENST00000672602.2		c.277G>A	p.Gly93Arg	missense	Exon 3 of 6	ENSP00000500814.2	A0A5F9ZI26

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 29

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	Charcot-Marie-Tooth disease type 1B (1)
1	-	-	Charcot-Marie-Tooth disease, type I (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.66	D
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Benign	0.85	D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Benign	-0.35	T
MutationAssessor	Uncertain	2.7	M
PhyloP100		3.6
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.1	D
REVEL	Uncertain	0.48
Sift	Benign	0.087	T
Sift4G	Benign	0.065	T
Polyphen		1.0	D
Vest4		0.84
MutPred		0.65		Gain of MoRF binding (P = 0.0542)
MVP		0.83
MPC		1.5
ClinPred		0.99	D
GERP RS		3.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.84
gMVP		0.98
Mutation Taster		=17/83	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.44		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.44		Position offset: 4

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

Other links and lift over

dbSNP: rs1553259691; hg19: chr1-161276669;