1-161305133-G-A

Variant names:

• chr1-161305133-G-A
• rs140992541
• ENST00000463290.5:n.*499C>T

Variant summary

Our verdict is Benign. The variant received -11 ACMG points: 0P and 11B. BP4_Moderate BP6 BS1 BS2

The NM_000530.8(MPZ):​c.*743C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000368 in 152,238 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00037 (0 hom., cov: 30)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MPZ NM_000530.8 3_prime_UTR
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: 3.01
• 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: 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

ACMG classification

Our verdict: Benign. The variant received -11 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.43).
• BP6: Variant 1-161305133-G-A is Benign according to our data. Variant chr1-161305133-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 293305.We mark this variant Benign, oryginal submissions are: {Uncertain_significance=1, Benign=3, Likely_benign=1}.
• BS1: Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.000368 (56/152238) while in subpopulation EAS AF = 0.0102 (53/5178). AF 95% confidence interval is 0.00804. There are 0 homozygotes in GnomAd4. There are 28 alleles in the male GnomAd4 subpopulation. Median coverage is 30. This position passed quality control check.
• BS2: High AC in GnomAd4 at 56 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MPZ	NM_000530.8	c.*743C>T		3_prime_UTR_variant	Exon 6 of 6	ENST00000533357.5	NP_000521.2
MPZ	NM_001315491.2	c.*551C>T		3_prime_UTR_variant	Exon 6 of 6		NP_001302420.1
MPZ	XM_017001321.3	c.676-792C>T		intron_variant	Intron 5 of 5		XP_016856810.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MPZ	ENST00000533357.5	c.*743C>T		3_prime_UTR_variant	Exon 6 of 6	1	NM_000530.8	ENSP00000432943.1

Frequencies

GnomAD3 genomes AF: 0.000362 AC: 55 AN: 152120 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.0100

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 706 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 438

African (AFR) AC: 0 AN: 0

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 2

East Asian (EAS) AF: 0.00 AC: 0 AN: 104

South Asian (SAS) AF: 0.00 AC: 0 AN: 22

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 436

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 126

Other (OTH) AF: 0.00 AC: 0 AN: 16

GnomAD4 genome AF: 0.000368 AC: 56 AN: 152238 Hom.: 0 Cov.: 30 AF XY: 0.000376 AC XY: 28 AN XY: 74424

African (AFR) AF: 0.00 AC: 0 AN: 41536

American (AMR) AF: 0.000131 AC: 2 AN: 15288

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.0102 AC: 53 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10602

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.000472

Asia WGS AF: 0.00115 AC: 4 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neuropathy, congenital hypomyelinating, 2 Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Roussy-Lévy syndrome Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Charcot-Marie-Tooth disease type 1B Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Charcot-Marie-Tooth disease dominant intermediate D Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Charcot-Marie-Tooth disease type 4E Benign:1

Jun 14, 2016

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.43
CADD	Benign	20
DANN	Benign	0.91
PhyloP100		3.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Mutation Taster		=99/1	polymorphism

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: rs140992541; hg19: chr1-161274923; COSMIC: COSV100337957; COSMIC: COSV100337957;