19-49864042-G-C
Variant summary
Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate
The NM_007254.4(PNKP):c.666C>G(p.Ile222Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. I222I) has been classified as Likely benign.
Frequency
Consequence
NM_007254.4 missense
Scores
Clinical Significance
Conservation
Publications
- ataxia - oculomotor apraxia type 4Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P, Laboratory for Molecular Medicine
- microcephaly, seizures, and developmental delayInheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)
- Charcot-Marie-Tooth disease type 2B2Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
- genetic developmental and epileptic encephalopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 2 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| PNKP | NM_007254.4 | c.666C>G | p.Ile222Met | missense_variant | Exon 7 of 17 | ENST00000322344.8 | NP_009185.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| PNKP | ENST00000322344.8 | c.666C>G | p.Ile222Met | missense_variant | Exon 7 of 17 | 1 | NM_007254.4 | ENSP00000323511.2 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152204Hom.: 0 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 250818 AF XY: 0.0000147 show subpopulations
GnomAD4 exome AF: 0.0000103 AC: 15AN: 1461618Hom.: 0 Cov.: 32 AF XY: 0.00000963 AC XY: 7AN XY: 727128 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152204Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1AN XY: 74360 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:2
- -
p.Ile222Met (ATC>ATG): c.666 C>G in exon 7 of the PNKP gene (NM_007254.2) A variant of unknown significance has been identified in the PNKP gene. The I222M variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It 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. This substitution occurs at a position that is highly conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. However, the I222M variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. The variant is found in EPILEPSY panel(s). -
Inborn genetic diseases Uncertain:1
The p.I222M variant (also known as c.666C>G), located in coding exon 6 of the PNKP gene, results from a C to G substitution at nucleotide position 666. The isoleucine at codon 222 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Developmental and epileptic encephalopathy, 12 Uncertain:1
This variant has not been reported in the literature in individuals with PNKP-related conditions. ClinVar contains an entry for this variant (Variation ID: 206389). This sequence change replaces isoleucine with methionine at codon 222 of the PNKP protein (p.Ile222Met). The isoleucine residue is highly conserved and there is a small physicochemical difference between isoleucine and methionine. This variant is present in population databases (rs587784369, ExAC 0.002%). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at