chr16-29812324-G-A

Position:

• chr16-29812324-G-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PM2 PP3_Strong

The NM_145239.3(PRRT2):​c.-66+1G>A variant causes a splice donor change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000197 in 152,220 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.000020 (0 hom., cov: 31)
• Consequence: PRRT2 NM_145239.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.755

Genes affected

PRRT2 (HGNC:30500): (proline rich transmembrane protein 2) This gene encodes a transmembrane protein containing a proline-rich domain in its N-terminal half. Studies in mice suggest that it is predominantly expressed in brain and spinal cord in embryonic and postnatal stages. Mutations in this gene are associated with episodic kinesigenic dyskinesia-1. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jan 2012]

LOC112268170 (HGNC:):

MVP-DT (HGNC:56029): (MVP divergent transcript)

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 7.2, offset of 28, new splice context is: cggGTagga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PRRT2	NM_145239.3	c.-66+1G>A		splice_donor_variant		ENST00000358758.12
LOC112268170	XM_047435008.1	c.123C>T	p.His41=	synonymous_variant	1/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PRRT2	ENST00000358758.12	c.-66+1G>A		splice_donor_variant		1	NM_145239.3	P1
MVP-DT	ENST00000569039.5	n.246-2151C>T		intron_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152220 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152220 Hom.: 0 Cov.: 31 AF XY: 0.0000134 AC XY: 1 AN XY: 74356

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000142 Hom.: 0

Bravo AF: 0.0000264

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 14, 2014

c.-66+1 G>A: IVS1+1 G>A in intron 1 of the PRRT2 gene (NM_145239.2)A variant of unknown significance has been identified in the PRRT2 gene. The c.-66+1 G>A variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. The c.-66+1 G>A variant destroys the canonical splice donor site of non-coding exon 1, either leading to the inclusion of abnormal sequence into the 5' UTR or deletion of sequence normally included in the 5' UTR. However, to our knowledge, no regulatory mutations have been reported in the PRRT2 gene. Additionally, in the absence of RNA/functional studies, the actual effect of the c.-66+1 G>A sequence change is unknown. 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). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	34
DANN	Benign	0.97

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.92
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.63		Position offset: 27
DS_DL_spliceai		0.99		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs796052939; hg19: chr16-29823645;