rs370329917

Positions:

• chr17-47943393-G-A
• chr17-47943393-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_018129.4(PNPO):​c.226G>A​(p.Gly76Arg) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,652 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 (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PNPO NM_018129.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.43

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Pyridoxine-5'-phosphate oxidase (size 260) in uniprot entity PNPO_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_018129.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.21710381).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PNPO	NM_018129.4	c.226G>A	p.Gly76Arg	missense_variant	2/7	ENST00000642017.2	NP_060599.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PNPO	ENST00000642017.2	c.226G>A	p.Gly76Arg	missense_variant	2/7		NM_018129.4	ENSP00000493302.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461652 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727128

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 25, 2024

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis indicates that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Pyridoxal phosphate-responsive seizures Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 28, 2021

This sequence change replaces glycine with arginine at codon 76 of the PNPO protein (p.Gly76Arg). The glycine residue is moderately conserved and there is a moderate physicochemical difference between glycine and arginine. 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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	0.25
BayesDel_addAF	Uncertain	0.030	T
BayesDel_noAF	Benign	-0.19
CADD	Benign	21
DANN	Benign	0.83
DEOGEN2	Benign	0.050	T;.;.;.
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.18
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.90	D;D;D;T
M_CAP	Benign	0.045	D
MetaRNN	Benign	0.22	T;T;T;T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	0.52	N;N;N;.
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.46	.;N;N;.
REVEL	Uncertain	0.29
Sift	Benign	0.42	.;T;T;.
Sift4G	Benign	0.53	.;T;T;.
Polyphen		0.90	P;.;.;.
Vest4		0.48, 0.53
MutPred		0.44		Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);Gain of solvent accessibility (P = 0.0037);.;
MVP		0.78
MPC		1.3
ClinPred		0.62	D
GERP RS		1.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.16
gMVP		0.69

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: rs370329917; hg19: chr17-46020759;