rs41270025

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_001122764.3(PPOX):c.503G>A(p.Arg168His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,970 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R168C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

PPOX
NM_001122764.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 8.27

Variant links:

Genes affected

PPOX (HGNC:9280): (protoporphyrinogen oxidase) This gene encodes the penultimate enzyme of heme biosynthesis, which catalyzes the 6-electron oxidation of protoporphyrinogen IX to form protoporphyrin IX. Mutations in this gene cause variegate porphyria, an autosomal dominant disorder of heme metabolism resulting from a deficiency in protoporphyrinogen oxidase, an enzyme located on the inner mitochondrial membrane. Alternatively spliced transcript variants encoding the same protein have been identified. [provided by RefSeq, Jul 2008]

PPOX links:

PPOX (HGNC:):

PPOX links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PM1

In a helix (size 8) in uniprot entity PPOX_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_001122764.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-161168462-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 8694.Status of the report is no_assertion_criteria_provided, 0 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.968

PP5

Variant 1-161168463-G-A is Pathogenic according to our data. Variant chr1-161168463-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 8697.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PPOX	NM_001122764.3 linkuse as main transcript	c.503G>A	p.Arg168His	missense_variant	6/13	ENST00000367999.9	NP_001116236.1	P50336

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PPOX	ENST00000367999.9 linkuse as main transcript	c.503G>A	p.Arg168His	missense_variant	6/13	1	NM_001122764.3	ENSP00000356978.4		P50336

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152084

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

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

AF:

6.84e-7

AC:

AN:

1461886

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727242

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152084

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74296

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Variegate porphyria

Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Centogene AG - the Rare Disease Company	Feb 28, 2019	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 01, 2001	- -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics Laboratory, University Hospital Schleswig-Holstein	Dec 01, 2022	- -

not provided

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 03, 2022	This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 168 of the PPOX protein (p.Arg168His). This variant is not present in population databases (gnomAD no frequency). For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects PPOX function (PMID: 11929051, 21048046). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt PPOX protein function. ClinVar contains an entry for this variant (Variation ID: 8697). This missense change has been observed in individuals with variegate porphyria (PMID: 9738863, 10486317, 11173967, 18570668, 19845869, 28653968). It has also been observed to segregate with disease in related individuals. -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 02, 2018	The R168H variant in the PPOX gene has been reported previously in association with variegate porphyria (Frank et al., 1998; Whatley et al., 1999; Frank et al., 2001; Rossetti et al., 2008). The R168H variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The R168H variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved across species. Functional studies demonstrate R168H disrupts the hydrogen bond network, and has a 50-fold decrease in catalytic activity (Qin et al., 2011). We interpret R168H as a pathogenic variant. -

See cases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Jul 02, 2020

ACMG classification criteria: PS3, PS4, PM2, PP1, PP2, PP4 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.43

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.87

D;D

Eigen

Uncertain

0.53

Eigen_PC

Uncertain

0.59

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.95

.;D

M_CAP

Uncertain

0.21

MetaRNN

Pathogenic

0.97

D;D

MetaSVM

Uncertain

0.17

MutationAssessor

Benign

1.2

L;L

PrimateAI

Uncertain

0.73

PROVEAN

Uncertain

-2.6

D;D

REVEL

Pathogenic

0.83

Sift

Uncertain

0.0040

D;D

Sift4G

Uncertain

0.034

D;D

Polyphen

1.0

D;D

Vest4

0.90

MutPred

0.86

Loss of methylation at R168 (P = 0.0725);Loss of methylation at R168 (P = 0.0725);

MVP

0.93

MPC

1.5

ClinPred

0.98

GERP RS

5.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.83

gMVP

0.73

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.040

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over