17-47941677-T-C

Variant names:

• chr17-47941677-T-C
• rs796052870
• NM_018129.4:c.2T>C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP5

The NM_018129.4(PNPO):​c.2T>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000124 in 1,534,978 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: PNPO NM_018129.4 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 2.20

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 5 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 1 pathogenic variants. Next in-frame start position is after 32 codons. Genomic position: 47941769. Lost 0.120 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-47941677-T-C is Pathogenic according to our data. Variant chr17-47941677-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 206456.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}. Variant chr17-47941677-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PNPO	NM_018129.4	c.2T>C	p.Met1?	start_lost	Exon 1 of 7	ENST00000642017.2	NP_060599.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNPO	ENST00000642017.2	c.2T>C	p.Met1?	start_lost	Exon 1 of 7		NM_018129.4	ENSP00000493302.2

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152178 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.0000130 AC: 18 AN: 1382800 Hom.: 0 Cov.: 31 AF XY: 0.0000132 AC XY: 9 AN XY: 679678

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: 0.0000159

Gnomad4 OTH exome AF: 0.0000175

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152178 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74346

Gnomad4 AFR AF: 0.0000241

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: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Pyridoxal phosphate-responsive seizures Pathogenic:1 Uncertain:1

Mar 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects the initiator methionine of the PNPO mRNA. The next in-frame methionine is located at codon 32. This variant is not present in population databases (gnomAD no frequency). 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: 206456). 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. -

May 02, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Jan 22, 2024

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Initiation codon variant in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	24
DANN	Uncertain	0.98
DEOGEN2	Benign	0.093	T;.;.
Eigen	Benign	-0.046
Eigen_PC	Benign	0.10
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Pathogenic	0.56	D
MetaRNN	Uncertain	0.68	D;D;D
MetaSVM	Benign	-0.60	T
PROVEAN	Benign	-0.61	.;N;N
REVEL	Uncertain	0.39
Sift	Pathogenic	0.0	.;D;D
Sift4G	Pathogenic	0.0	.;D;D
Polyphen		0.039	B;.;.
Vest4		0.77, 0.71
MVP		0.91
ClinPred		0.99	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.88
gMVP		0.68

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: rs796052870; hg19: chr17-46019043;