21-32688315-G-C

Position:

• chr21-32688315-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_203446.3(SYNJ1):​c.842C>G​(p.Ala281Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SYNJ1 NM_203446.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.24

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.866

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SYNJ1	NM_203446.3	c.842C>G	p.Ala281Gly	missense_variant	7/33	ENST00000674351.1	NP_982271.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SYNJ1	ENST00000674351.1	c.842C>G	p.Ala281Gly	missense_variant	7/33		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

Jul 24, 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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 replaces alanine with glycine at codon 320 of the SYNJ1 protein (p.Ala320Gly). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and glycine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.010
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.43	.;T;.;T;T;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D
M_CAP	Benign	0.026	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D
MetaSVM	Uncertain	-0.015	T
MutationAssessor	Uncertain	2.6	M;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-3.3	D;D;.;D;D;D
REVEL	Uncertain	0.51
Sift	Uncertain	0.019	D;D;.;D;D;D
Sift4G	Uncertain	0.0070	D;D;D;D;D;.
Polyphen		1.0	D;.;.;D;.;.
Vest4		0.63
MutPred		0.71		Gain of disorder (P = 0.0974);Gain of disorder (P = 0.0974);Gain of disorder (P = 0.0974);.;.;Gain of disorder (P = 0.0974);
MVP		0.84
MPC		1.5
ClinPred		0.99	D
GERP RS		6.2
gMVP		0.53

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: rs1046699971; hg19: chr21-34060625;