rs769985808

chr17-47944675-G-Achr17-47944675-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_018129.4(PNPO):c.323G>A(p.Arg108His) variant causes a missense change. The variant allele was found at a frequency of 0.00000929 in 1,613,994 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R108C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000089 (0 hom.)
• Consequence: PNPO NM_018129.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.05

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 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=0.30556083).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PNPO	NM_018129.4	c.323G>A	p.Arg108His	missense_variant	3/7	ENST00000642017.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PNPO	ENST00000642017.2	c.323G>A	p.Arg108His	missense_variant	3/7		NM_018129.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152160 Hom.: 0 Cov.: 32

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000889 AC: 13 AN: 1461834 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727222

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000504

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000989

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152160 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74344

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: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000108 Hom.: 0

Bravo AF: 0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Pyridoxal phosphate-responsive seizures Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 01, 2021

This sequence change replaces arginine with histidine at codon 108 of the PNPO protein (p.Arg108His). The arginine residue is moderately conserved and there is a small physicochemical difference between arginine and histidine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with PNPO-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The histidine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.014	T
BayesDel_noAF	Benign	-0.26
Cadd	Uncertain	24
Dann	Uncertain	0.99
DEOGEN2	Benign	0.032	T;T;.;.;.
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.063
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.96	D;D;D;D;D
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.31	T;T;T;T;T
MetaSVM	Benign	-0.87	T
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Benign	0.46	T
Sift4G	Benign	0.65	T;.;T;T;.
Polyphen		0.027	.;B;.;.;.
Vest4		0.22, 0.24
MutPred		0.56		.;Loss of MoRF binding (P = 0.0082);Loss of MoRF binding (P = 0.0082);Loss of MoRF binding (P = 0.0082);.;
MVP		0.69
MPC		0.59
ClinPred		0.86	D
GERP RS		2.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.41
gMVP		0.64

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

Other links and lift over

dbSNP: rs769985808; hg19: chr17-46022041; COSMIC: COSV99846555; COSMIC: COSV99846555;