19-49864236-C-G

Variant names:

• chr19-49864236-C-G
• rs145904995
• NM_007254.4:c.579G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_007254.4(PNKP):​c.579G>C​(p.Arg193Ser) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,838 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R193K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: PNKP NM_007254.4 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.53
• 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: Laboratory for Molecular Medicine, G2P, Orphanet
• microcephaly, seizures, and developmental delay

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, ClinGen
• 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: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_007254.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PNKP	NM_007254.4	MANE Select	c.579G>C	p.Arg193Ser	missense splice_region	Exon 6 of 17	NP_009185.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PNKP	ENST00000322344.8	TSL:1 MANE Select	c.579G>C	p.Arg193Ser	missense splice_region	Exon 6 of 17	ENSP00000323511.2	Q96T60-1
	PNKP	ENST00000596014.5	TSL:1	c.579G>C	p.Arg193Ser	missense splice_region	Exon 5 of 16	ENSP00000472300.1	Q96T60-1
	PNKP	ENST00000593946.5	TSL:1	n.*506G>C		splice_region non_coding_transcript_exon	Exon 5 of 16	ENSP00000468896.1	M0QX49

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461838 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727224

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53398

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111982

Other (OTH) AF: 0.00 AC: 0 AN: 60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
BayesDel_addAF	Benign	-0.013	T
BayesDel_noAF	Benign	-0.26
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.044	T
Eigen	Benign	0.14
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
MetaRNN	Uncertain	0.54	D
MetaSVM	Benign	-0.86	T
MutationAssessor	Benign	1.5	L
PhyloP100		3.5
PrimateAI	Benign	0.37	T
PROVEAN	Uncertain	-2.6	D
REVEL	Benign	0.19
Sift	Uncertain	0.0090	D
Sift4G	Uncertain	0.016	D
Polyphen		0.29	B
Vest4		0.48
MutPred		0.76		Loss of catalytic residue at R193 (P = 0.0571)
MVP		0.76
MPC		0.29
ClinPred		0.96	D
GERP RS		5.1
Varity_R		0.74
gMVP		0.64
Mutation Taster		=37/63	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.41		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.41		Position offset: 0

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

Other links and lift over

dbSNP: rs145904995; hg19: chr19-50367493;