19-40395701-C-T

Variant names:

• chr19-40395701-C-T
• rs139005780
• NM_181882.3:c.2651G>A

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2 BP4

The NM_181882.3(PRX):​c.2651G>A​(p.Gly884Asp) 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 benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G884G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: PRX NM_181882.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.190
• Publications: 0 publications found

Genes affected

PRX (HGNC:13797): (periaxin) This gene encodes a protein involved in peripheral nerve myelin upkeep. The encoded protein contains 2 PDZ domains which were named after PSD95 (post synaptic density protein), DlgA (Drosophila disc large tumor suppressor), and ZO1 (a mammalian tight junction protein). Two alternatively spliced transcript variants have been described for this gene which encode different protein isoforms and which are targeted differently in the Schwann cell. Mutations in this gene cause Charcot-Marie-Tooth neuoropathy, type 4F and Dejerine-Sottas neuropathy. [provided by RefSeq, Jul 2008]

PRX Gene-Disease associations (from GenCC):

• Charcot-Marie-Tooth disease type 4

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Charcot-Marie-Tooth disease type 4F

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics
• Charcot-Marie-Tooth disease type 3

  Inheritance: AD, AR Classification: MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.41253304).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PRX	NM_181882.3	c.2651G>A	p.Gly884Asp	missense_variant	Exon 7 of 7	ENST00000324001.8	NP_870998.2
PRX	NM_001411127.1	c.2936G>A	p.Gly979Asp	missense_variant	Exon 7 of 7		NP_001398056.1
PRX	XM_017027047.2	c.2549G>A	p.Gly850Asp	missense_variant	Exon 4 of 4		XP_016882536.1
PRX	NM_020956.2	c.*2856G>A		3_prime_UTR_variant	Exon 6 of 6		NP_066007.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PRX	ENST00000324001.8	c.2651G>A	p.Gly884Asp	missense_variant	Exon 7 of 7	1	NM_181882.3	ENSP00000326018.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 96

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 4 Uncertain:1

Sep 25, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with PRX-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with aspartic acid at codon 884 of the PRX protein (p.Gly884Asp). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and aspartic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.40
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.71	D
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.35
FATHMM_MKL	Benign	0.45	N
LIST_S2	Benign	0.51	T
M_CAP	Benign	0.055	D
MetaRNN	Benign	0.41	T
MetaSVM	Benign	-0.61	T
MutationAssessor	Uncertain	2.5	M
PhyloP100		0.19
PrimateAI	Benign	0.35	T
PROVEAN	Uncertain	-4.4	D
REVEL	Benign	0.15
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0030	D
Polyphen		0.96	D
Vest4		0.41
MVP		0.41
MPC		0.94
ClinPred		0.94	D
GERP RS		2.5
Varity_R		0.40
gMVP		0.39
Mutation Taster		=94/6	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: rs139005780; hg19: chr19-40901608;