NM_018129.4:c.448_451delCCTG

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_018129.4(PNPO):c.448_451delCCTG(p.Pro150ArgfsTer27) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,726 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P150P) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

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

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

PNPO
NM_018129.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 7.77

Publications

5 publications found

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 Gene-Disease associations (from GenCC):

pyridoxal phosphate-responsive seizures
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, ClinGen, Labcorp Genetics (formerly Invitae), Orphanet

PNPO links:

ENSG00000263798 (HGNC:):

ENSG00000263798 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 17-47945887-ACTGC-A is Pathogenic according to our data. Variant chr17-47945887-ACTGC-A is described in ClinVar as Pathogenic. ClinVar VariationId is 206460.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PNPO	NM_018129.4 link	c.448_451delCCTG	p.Pro150ArgfsTer27	frameshift_variant	Exon 5 of 7	ENST00000642017.2	NP_060599.1	Q9NVS9-1V9HW45
PNPO	NM_001436305.1 link	c.417+279_417+282delCCTG		intron_variant	Intron 4 of 5		NP_001423234.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNPO	ENST00000642017.2 link	c.448_451delCCTG	p.Pro150ArgfsTer27	frameshift_variant	Exon 5 of 7		NM_018129.4	ENSP00000493302.2		Q9NVS9-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

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:

0.000193

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

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251026

AF XY:

0.00000737

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000217

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461554

Hom.:

AF XY:

0.00000275

AC XY:

AN XY:

727060

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.000126

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53094

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74350

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000151

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Pyridoxal phosphate-responsive seizures

Pathogenic:2

Mar 12, 2015

Knight Diagnostic Laboratories, Oregon Health and Sciences University

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Mar 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Pro150Argfs*27) in the PNPO gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PNPO are known to be pathogenic (PMID: 15772097, 24645144). This variant is present in population databases (rs775105142, gnomAD 0.02%). This premature translational stop signal has been observed in individual(s) with clinical features of pyridoxal 5'-phosphate-dependent epilepsy (PMID: 28349276, 29588952). ClinVar contains an entry for this variant (Variation ID: 206460). For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:1

Nov 07, 2014

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

c.448_451delCCTG: p.Pro150ArgfsX27 in exon 5 in the PNPO gene (NM_018129.3). The normal sequence with the bases that are deleted in braces is: ACTG{CCTG}AGGA. The maternally inherited c.448_451delCCTG mutation in the PNPO gene has not been reported previously as a disease-causing mutation nor as a benign polymorphism, to our knowledge. The c.448_451delCCTG mutation causes a frameshift starting with codon Proline 150, changes this amino acid to a Arginine residue and creates a premature Stop codon at position 27 of the new reading frame, denoted p.Pro150ArgfsX27. This mutation is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The c.448_451delCCTG mutation was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.448_451delCCTG as a disease-causing mutation. This variant has been observed to be maternally inherited The variant is found in PNPO, panel(s). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

7.8

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over