2-218270537-T-G

Position:

• chr2-218270537-T-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The ENST00000273077.9(PNKD):​c.2T>G​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,076,938 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 (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000074 (0 hom.)
• Consequence: PNKD ENST00000273077.9 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.45

Genes affected

PNKD (HGNC:9153): (PNKD metallo-beta-lactamase domain containing) This gene is thought to play a role in the regulation of myofibrillogenesis. Mutations in this gene have been associated with the movement disorder paroxysmal non-kinesigenic dyskinesia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PNKD	NM_015488.5	c.2T>G	p.Met1?	start_lost	1/10	ENST00000273077.9	NP_056303.3
PNKD	NM_001077399.3	c.2T>G	p.Met1?	start_lost	1/3		NP_001070867.1
PNKD	XM_017003771.2	c.2T>G	p.Met1?	start_lost	1/9		XP_016859260.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PNKD	ENST00000273077.9	c.2T>G	p.Met1?	start_lost	1/10	1	NM_015488.5	ENSP00000273077

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000743 AC: 8 AN: 1076938 Hom.: 0 Cov.: 17 AF XY: 0.00000386 AC XY: 2 AN XY: 517730

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000908

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000909 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Paroxysmal nonkinesigenic dyskinesia 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

The PNKD c.2T>G (p.Met1?) variant is predicted to disrupt the initiator codon, and may potentially interfere with protein expression. A literature search was performed for the gene, cDNA change, and amino acid change. No publications were found based on this search. The variant is reported at a frequency of 0.00014 in the European (non-Finnish) population of the Exome Aggregation Consortium but this is based on one allele, but in a region of poor sequence coverage. Based on the variant frequency, disease prevalence, disease penetrance, and inheritance mode, this variant could not be ruled out of causing disease. Due to the potential impact on protein expression and the lack of clarifying evidence, the p.Met1? variant is classified as a variant of unknown significance but suspicious for pathogenicity for familial paroxysmal nonkinesigenic dyskinesia. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.67
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Benign	0.18	.;T
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Benign	0.48	N
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.91	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D
PROVEAN	Benign	-0.68	N;N
REVEL	Pathogenic	0.73
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.0080	D;D
Polyphen		0.99	D;P
Vest4		0.85
MutPred		0.96		Gain of methylation at M1 (P = 0.0075);Gain of methylation at M1 (P = 0.0075);
MVP		0.87
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.98
gMVP		0.80

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

Publications

LitVar

Other links and lift over

dbSNP: rs775653461; hg19: chr2-219135260;