21-32638993-T-TG

Position:

• chr21-32638993-T-TG

Variant summary

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

The NM_203446.3(SYNJ1):​c.3829_3830insC​(p.Gln1277ProfsTer19) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SYNJ1 NM_203446.3 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.20

Genes affected

SYNJ1 (HGNC:11503): (synaptojanin 1) This gene encodes a phosphoinositide phosphatase that regulates levels of membrane phosphatidylinositol-4,5-bisphosphate. As such, expression of this enzyme may affect synaptic transmission and membrane trafficking. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2011]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SYNJ1	NM_203446.3	c.3829_3830insC	p.Gln1277ProfsTer19	frameshift_variant	31/33	ENST00000674351.1	NP_982271.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SYNJ1	ENST00000674351.1	c.3829_3830insC	p.Gln1277ProfsTer19	frameshift_variant	31/33		NM_203446.3	ENSP00000501530

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early-onset Parkinson disease 20;C4479313:Developmental and epileptic encephalopathy, 53 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2017

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. This variant has not been reported in the literature in individuals with SYNJ1-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change results in a premature translational stop signal in the SYNJ1 gene (p.Gln1316Profs*19). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 297 amino acids of the SYNJ1 protein. -

Computational scores

Source: dbNSFP v4.3

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: rs1555888341; hg19: chr21-34011303;