19-49862702-T-A

Variant names:

• chr19-49862702-T-A
• rs750224965
• NM_007254.4:c.853A>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_007254.4(PNKP):​c.853A>T​(p.Ile285Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict 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. I285V) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: PNKP NM_007254.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.03
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• ataxia - oculomotor apraxia type 4

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P, Laboratory for Molecular Medicine
• microcephaly, seizures, and developmental delay

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• Charcot-Marie-Tooth disease type 2B2

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.061818212).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PNKP	NM_007254.4	c.853A>T	p.Ile285Phe	missense_variant	Exon 9 of 17	ENST00000322344.8	NP_009185.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PNKP	ENST00000322344.8	c.853A>T	p.Ile285Phe	missense_variant	Exon 9 of 17	1	NM_007254.4	ENSP00000323511.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 12 Uncertain:1

Jun 22, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with PNKP-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with phenylalanine at codon 285 of the PNKP protein (p.Ile285Phe). The isoleucine residue is weakly conserved and there is a small physicochemical difference between isoleucine and phenylalanine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.63
CADD	Benign	0.099
DANN	Benign	0.75
DEOGEN2	Benign	0.043	T;T;T;T;T
Eigen	Benign	-1.9
Eigen_PC	Benign	-1.9
FATHMM_MKL	Benign	0.041	N
LIST_S2	Uncertain	0.86	D;.;D;D;T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.062	T;T;T;T;T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	-0.84	.;N;.;N;.
PhyloP100		-2.0
PrimateAI	Benign	0.40	T
PROVEAN	Benign	3.3	.;N;.;.;.
REVEL	Benign	0.095
Sift	Benign	1.0	.;T;.;.;.
Sift4G	Benign	0.68	T;T;T;T;T
Polyphen		0.0	.;B;.;B;.
Vest4		0.29
MutPred		0.62		Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);.;Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);
MVP		0.18
MPC		0.14
ClinPred		0.052	T
GERP RS		-6.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.033
gMVP		0.59
Mutation Taster		=75/25	polymorphism

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

Other links and lift over

dbSNP: rs750224965; hg19: chr19-50365959;