dbSNP rs587784366: PNKP:p.Ala432fs (chr19-49861765-ACGCTACCTGG-A) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_007254.4(PNKP):c.1295_1298+6delCCAGGTAGCG(p.Ala432fs) variant causes a frameshift, splice donor, splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000046 in 1,566,646 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000047 ( 0 hom. )

Consequence

PNKP
NM_007254.4 frameshift, splice_donor, splice_region, intron

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 3.56

Variant links:

Genes affected

PNKP (HGNC:9154): (polynucleotide kinase 3'-phosphatase) This locus represents a gene involved in DNA repair. In response to ionizing radiation or oxidative damage, the protein encoded by this locus catalyzes 5' phosphorylation and 3' dephosphorylation of nucleic acids. Mutations at this locus have been associated with microcephaly, seizures, and developmental delay.[provided by RefSeq, Sep 2010]

PNKP links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 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 19-49861765-ACGCTACCTGG-A is Pathogenic according to our data. Variant chr19-49861765-ACGCTACCTGG-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 159788.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
PNKP	NM_007254.4 link	c.1295_1298+6delCCAGGTAGCG	p.Ala432fs	frameshift_variant, splice_donor_variant, splice_region_variant, intron_variant	Exon 14 of 17	ENST00000322344.8	NP_009185.2	Q96T60-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNKP	ENST00000322344.8 link	c.1295_1298+6delCCAGGTAGCG	p.Ala432fs	frameshift_variant, splice_donor_variant, splice_region_variant, intron_variant	Exon 14 of 17	1	NM_007254.4	ENSP00000323511.2		Q96T60-1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152120

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:

0.00

Gnomad SAS

AF:

0.000621

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000683

AC:

AN:

175710

Hom.:

AF XY:

0.0000848

AC XY:

AN XY:

94316

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000286

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000685

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000474

AC:

AN:

1414526

Hom.:

AF XY:

0.0000586

AC XY:

AN XY:

699848

show subpopulations

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:

0.000296

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000349

Gnomad4 OTH exome

AF:

0.0000854

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152120

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74298

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000621

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000227

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

Sep 19, 2013

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1295_1298+6delCCAGGTAGCG mutation in the PNKP gene results in the deletion of ten nucleotides at the exon 14/intron 14 boundary, thereby destroying the canonical splice donor site in intron 14. It is predicted to cause abnormal gene splicing, either leading to an abnormal message that is subject to nonsense-mediated mRNA decay or to an abnormal protein product if the message is used for protein translation. Although this mutation has not been previously reported to our knowledge, it is considered a disease-causing mutation.The variant is found in CHILD-EPI,EPILEPSY panel(s). -

Jun 28, 2016

Eurofins Ntd Llc (ga)

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 06, 2021

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Ataxia, early-onset, with oculomotor apraxia and hypoalbuminemia

Pathogenic:1

Dec 19, 2023

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1295_1298+6del (NM_007254.3 c.1295_1298+6delCCAGGTAGCG) variant in PNKP has been reported in the compound heterozygous state in 1 individual with microcephaly with early onset seizures (MCSZ), in 1 individual with motor neuropathy, and in 2 individuals with ataxia with oculomotor apraxia and segregated with disease in 2 affected relatives from 1 family (Previtali 2019 PMID: 31167812, Kalasova 2019 PMID: 31041400, da Costa 2022 PMID: 35426160). This variant has also been reported by other clinical laboratories in ClinVar (Variation ID 159788) and has been identified in 0.06% (3/4832) of South Asian and 0.0029% (2/68006) of European chromosomes by gnomAD (http://gnomad.broadinstitute.org, v.3.1.2). This variant is a deletion of ten nucleotides at the exon 14/intron 14 boundary, thereby destroying the canonical splice donor site in intron 14. It is predicted to cause altered splicing, leading to an abnormal or absent protein. Biallelic loss of function of the PNKP gene has been associated with ataxia with oculomotor apraxia. Functional studies in patient fibroblasts provide some evidence that this variant reduced protein expression and activity and were more susceptible to single strand breaks due to reduced repair activity (Kalasova 2019 PMID: 31041400, Kalasova 2020 PMID: 32504494). In summary, the c.1295_1298+6delCCAGGTAGCG variant in PNKP meets criteria to be classified as pathogenic for PNKP-related disorders, such as autosomal recessive ataxia with oculomotor apraxia, and autosomal recessive microcephaly, seizures and developmental delay. ACMG/AMP Criteria applied: PVS1, PM3_Strong, PP1, PS3_Supporting. -

Microcephaly, seizures, and developmental delay

Pathogenic:1

Jun 05, 2014

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

PNKP-related disorder

Pathogenic:1

Jun 06, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: PNKP c.1295_1298+6del10 is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a 5' splicing donor site. The variant allele was found at a frequency of 6.8e-05 in 175710 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in PNKP causing PNKP-Related Disorders, allowing no conclusion about variant significance. The variant, c.1295_1298+6del10, has been reported in the literature in multiple individuals affected with PNKP-Related Disorders ranging from microcephaly with early onset seizures to oculomotor apraxia and Charcot-Marie-Tooth type 2 (CMT2) disease (e.g. Previtali_2019, Kalasova_2020, daCosta_2022). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, and demonstrated strongly reduced protein level and reduced function in patient derived cells (Kalasova_2020). The following publications have been ascertained in the context of this evaluation (PMID: 31167812, 32504494, 35426160). ClinVar contains an entry for this variant (Variation ID: 159788). Based on the evidence outlined above, the variant was classified as pathogenic. -

Developmental and epileptic encephalopathy, 12

Pathogenic:1

Jun 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant results in the deletion of part of exon 14 (c.1295_1298+6del) of the PNKP gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in PNKP are known to be pathogenic (PMID: 20118933, 25728773). This variant is present in population databases (rs587784366, gnomAD 0.03%). This variant has been observed in individual(s) with PNKP-related conditions (PMID: 31167812). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 159788). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this variant affects PNKP function (PMID: 32504494). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

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