Genetic Variant SNCA:c.306+27220G>A (chr4-89795026-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000345.4(SNCA):c.306+27220G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000263 in 151,948 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Consequence

SNCA
NM_000345.4 intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.140

Publications

8 publications found

Variant links:

Genes affected

SNCA (HGNC:11138): (synuclein alpha) Alpha-synuclein is a member of the synuclein family, which also includes beta- and gamma-synuclein. Synucleins are abundantly expressed in the brain and alpha- and beta-synuclein inhibit phospholipase D2 selectively. SNCA may serve to integrate presynaptic signaling and membrane trafficking. Defects in SNCA have been implicated in the pathogenesis of Parkinson disease. SNCA peptides are a major component of amyloid plaques in the brains of patients with Alzheimer's disease. Alternatively spliced transcripts encoding different isoforms have been identified for this gene. [provided by RefSeq, Feb 2016]

SNCA Gene-Disease associations (from GenCC):

autosomal dominant Parkinson disease 4
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae)
Parkinson disease
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen, Ambry Genetics
autosomal dominant Parkinson disease 1
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
Lewy body dementia
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
hereditary late onset Parkinson disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
parkinsonian-pyramidal syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

SNCA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.92).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SNCA	NM_000345.4 link	c.306+27220G>A		intron_variant	Intron 4 of 5	ENST00000394991.8	NP_000336.1	P37840-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SNCA	ENST00000394991.8 link	c.306+27220G>A		intron_variant	Intron 4 of 5	1	NM_000345.4	ENSP00000378442.4		P37840-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

151948

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

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:

0.000189

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome

AF:

0.0000263

AC:

AN:

151948

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74208

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41350

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.000189

AC:

AN:

10556

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67984

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.92

CADD

Benign

4.6

(source)

DANN

Benign

0.82

PhyloP100

-0.14

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over