chr21-32656885-A-T

Variant names:

• chr21-32656885-A-T
• rs114053718
• NM_203446.3:c.2597T>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_203446.3(SYNJ1):​c.2597T>A​(p.Ile866Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,822 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I866T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SYNJ1 NM_203446.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.10
• Publications: 0 publications found

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]

SYNJ1 Gene-Disease associations (from GenCC):

• genetic developmental and epileptic encephalopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 53

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• early-onset Parkinson disease 20

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• atypical juvenile parkinsonism

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• young-onset Parkinson disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.911

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SYNJ1	NM_203446.3	c.2597T>A	p.Ile866Asn	missense_variant	Exon 21 of 33	ENST00000674351.1	NP_982271.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SYNJ1	ENST00000674351.1	c.2597T>A	p.Ile866Asn	missense_variant	Exon 21 of 33		NM_203446.3	ENSP00000501530.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461822 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727204

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39684

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111988

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.51	.;D;.;D;D
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D;D;D;D;D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.91	D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.8	M;.;.;.;.
PhyloP100		9.1
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-5.9	D;D;.;D;D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	D;D;.;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Polyphen		0.90	P;.;.;P;.
Vest4		0.94
MutPred		0.71		Gain of catalytic residue at I866 (P = 0.003);.;.;.;.;
MVP		0.96
MPC		0.71
ClinPred		1.0	D
GERP RS		5.6
gMVP		0.97
Mutation Taster		=40/60	disease causing

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

Other links and lift over

dbSNP: rs114053718; hg19: chr21-34029195;