rs145461623

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 4P and 5B. PM1PM2BP4_StrongBS1_Supporting

The NM_018129.4(PNPO):c.167T>G(p.Leu56Arg) variant causes a missense change. The variant allele was found at a frequency of 0.0000663 in 1,614,016 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 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. L56L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

PNPO
NM_018129.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 3.83

Variant links:

Genes affected

PNPO (HGNC:30260): (pyridoxamine 5'-phosphate oxidase) The enzyme encoded by this gene catalyzes the terminal, rate-limiting step in the synthesis of pyridoxal 5'-phosphate, also known as vitamin B6. Vitamin B6 is a required co-factor for enzymes involved in both homocysteine metabolism and synthesis of neurotransmitters such as catecholamine. Mutations in this gene result in pyridoxamine 5'-phosphate oxidase (PNPO) deficiency, a form of neonatal epileptic encephalopathy. [provided by RefSeq, Oct 2008]

PNPO links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM1

In a chain Pyridoxine-5'-phosphate oxidase (size 260) in uniprot entity PNPO_HUMAN there are 19 pathogenic changes around while only 2 benign (90%) in NM_018129.4

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.019527763).

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000459 (70/152374) while in subpopulation AFR AF= 0.00149 (62/41586). AF 95% confidence interval is 0.00119. There are 0 homozygotes in gnomad4. There are 33 alleles in male gnomad4 subpopulation. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PNPO	NM_018129.4 linkuse as main transcript	c.167T>G	p.Leu56Arg	missense_variant	2/7	ENST00000642017.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PNPO	ENST00000642017.2 linkuse as main transcript	c.167T>G	p.Leu56Arg	missense_variant	2/7		NM_018129.4	P1	Q9NVS9-1

Frequencies

GnomAD3 genomes

AF:

0.000460

AC:

AN:

152256

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00150

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000523

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000111

AC:

AN:

251472

Hom.:

AF XY:

0.0000662

AC XY:

AN XY:

135912

show subpopulations

Gnomad AFR exome

AF:

0.00154

Gnomad AMR exome

AF:

0.0000867

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000253

AC:

AN:

1461642

Hom.:

Cov.:

AF XY:

0.0000303

AC XY:

AN XY:

727142

show subpopulations

Gnomad4 AFR exome

AF:

0.00102

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.000459

AC:

AN:

152374

Hom.:

Cov.:

AF XY:

0.000443

AC XY:

AN XY:

74518

show subpopulations

Gnomad4 AFR

AF:

0.00149

Gnomad4 AMR

AF:

0.000523

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000139

Hom.:

Bravo

AF:

0.000589

ESP6500AA

AF:

0.00250

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000181

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jan 16, 2019	A variant of uncertain significance has been identified in the PNPO gene. The L56R variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The L56R variant is observed in 20/10392 (0.2%) alleles from individuals of African background in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The L56R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species. In silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Jun 24, 2019	- -

Pyridoxal phosphate-responsive seizures

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Oct 25, 2022	This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 56 of the PNPO protein (p.Leu56Arg). This variant is present in population databases (rs145461623, gnomAD 0.2%). This variant has not been reported in the literature in individuals affected with PNPO-related conditions. ClinVar contains an entry for this variant (Variation ID: 206441). 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 PNPO protein function. 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. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 16, 2018

The p.L56R variant (also known as c.167T>G), located in coding exon 2 of the PNPO gene, results from a T to G substitution at nucleotide position 167. The leucine at codon 56 is replaced by arginine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.072

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Uncertain

-0.060

Cadd

Benign

Dann

Benign

0.80

DEOGEN2

Benign

0.062

T;.;.;.

Eigen

Benign

-0.24

Eigen_PC

Benign

-0.12

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.80

T;T;T;T

M_CAP

Benign

0.074

MetaRNN

Benign

0.020

T;T;T;T

MetaSVM

Benign

-0.65

MutationAssessor

Benign

2.0

M;M;M;.

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.60

Polyphen

0.11

B;.;.;.

Vest4

0.22, 0.26

MVP

0.87

MPC

0.68

ClinPred

0.039

GERP RS

4.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.35

gMVP

0.63

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

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