X-47573994-C-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_006950.3(SYN1):c.1982+8G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0 (0 hom. 0 hem.)
  • Failed GnomAD Quality Control
• Consequence: SYN1 NM_006950.3 splice_region, intron
• Scores: Splicing: ADA: 0.0002715
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.71

Genes affected

SYN1 (HGNC:11494): (synapsin I) This gene is a member of the synapsin gene family. Synapsins encode neuronal phosphoproteins which associate with the cytoplasmic surface of synaptic vesicles. Family members are characterized by common protein domains, and they are implicated in synaptogenesis and the modulation of neurotransmitter release, suggesting a potential role in several neuropsychiatric diseases. This member of the synapsin family plays a role in regulation of axonogenesis and synaptogenesis. The protein encoded serves as a substrate for several different protein kinases and phosphorylation may function in the regulation of this protein in the nerve terminal. Mutations in this gene may be associated with X-linked disorders with primary neuronal degeneration such as Rett syndrome. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.57).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYN1	NM_006950.3	c.1982+8G>T		splice_region_variant, intron_variant		ENST00000295987.13
SYN1	NM_133499.2	c.1982+8G>T		splice_region_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYN1	ENST00000295987.13	c.1982+8G>T		splice_region_variant, intron_variant		2	NM_006950.3	P3
SYN1	ENST00000340666.5	c.1982+8G>T		splice_region_variant, intron_variant		1		A1
SYN1	ENST00000640721.1	c.70+694G>T		intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1017734 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 324878

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

Bravo AF: 0.0000302

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

X-linked epilepsy-learning disabilities-behavior disorders syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 12, 2021

This sequence change falls in intron 12 of the SYN1 gene. It does not directly change the encoded amino acid sequence of the SYN1 protein. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has been observed in individual(s) with clinical features of SYN1-related conditions (Invitae). Experimental studies and prediction algorithms are not available or were not evaluated, and the effect of this variant on mRNA splicing is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.57
Cadd	Benign	15
Dann	Benign	0.88

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00027
dbscSNV1_RF	Benign	0.078
SpliceAI score (max)		0.030		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: rs1015222436; hg19: chrX-47433393;