21-32681590-C-T

Variant names:

• chr21-32681590-C-T
• rs1060499619
• NM_203446.3:c.1259G>A
• SYNJ1 p.Arg420His

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PM5

The NM_203446.3(SYNJ1):​c.1259G>A​(p.Arg420His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,538 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R420P) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SYNJ1 NM_203446.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.86
• 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: Ambry Genetics, Labcorp Genetics (formerly Invitae), PanelApp Australia
• early-onset Parkinson disease 20

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia
• 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
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr21-32681590-C-G is described in ClinVar as Pathogenic. ClinVar VariationId is 393356.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_203446.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNJ1	NM_203446.3	MANE Select	c.1259G>A	p.Arg420His	missense	Exon 11 of 33	NP_982271.3	O43426-2
	SYNJ1	NM_003895.4		c.1376G>A	p.Arg459His	missense	Exon 11 of 32	NP_003886.3
	SYNJ1	NM_001160306.2		c.1259G>A	p.Arg420His	missense	Exon 11 of 28	NP_001153778.1	A0A0D9SGJ6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNJ1	ENST00000674351.1	MANE Select	c.1259G>A	p.Arg420His	missense	Exon 11 of 33	ENSP00000501530.1	O43426-2
	SYNJ1	ENST00000630077.3	TSL:1	c.1259G>A	p.Arg420His	missense	Exon 11 of 28	ENSP00000487560.1	A0A0D9SGJ6
	SYNJ1	ENST00000429236.5	TSL:1	c.1259G>A	p.Arg420His	missense	Exon 11 of 16	ENSP00000413649.1	C9JW66

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461538 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727090

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39634

South Asian (SAS) AF: 0.00 AC: 0 AN: 86228

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111810

Other (OTH) AF: 0.00 AC: 0 AN: 60376

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000343967), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Early-onset Parkinson disease 20;C4479313:Developmental and epileptic encephalopathy, 53 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.40	T
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Benign	0.034	D
MetaRNN	Uncertain	0.74	D
MetaSVM	Benign	-0.76	T
MutationAssessor	Uncertain	2.1	M
PhyloP100		7.9
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-4.6	D
REVEL	Uncertain	0.46
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
gMVP		0.67
Mutation Taster		=32/68	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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1060499619;

hg19: chr21-34053900;

COSMIC: COSV108157885;