chrX-47574018-G-A

Position:

• chrX-47574018-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_006950.3(SYN1):​c.1966C>T​(p.Pro656Ser) variant causes a missense 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. 12/20 in silico tools predict a benign outcome for this variant. 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. P656L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0 (0 hom. 0 hem.)
  • Failed GnomAD Quality Control
• Consequence: SYN1 NM_006950.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 2.51

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 Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1418246).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYN1	NM_006950.3	c.1966C>T	p.Pro656Ser	missense_variant	12/13	ENST00000295987.13
SYN1	NM_133499.2	c.1966C>T	p.Pro656Ser	missense_variant	12/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYN1	ENST00000295987.13	c.1966C>T	p.Pro656Ser	missense_variant	12/13	2	NM_006950.3	P3
SYN1	ENST00000340666.5	c.1966C>T	p.Pro656Ser	missense_variant	12/13	1		A1
SYN1	ENST00000640721.1	c.70+670C>T		intron_variant		5

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1034557 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 332783

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

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

SYN1-related disorder Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Sep 08, 2024

The SYN1 c.1966C>T variant is predicted to result in the amino acid substitution p.Pro656Ser. To our knowledge, this variant has not been reported in the literature or in a large population database, indicating this variant is rare. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Epilepsy, X-linked 1, with variable learning disabilities and behavior disorders Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 29, 2023

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. Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant has not been reported in the literature in individuals affected with SYN1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 656 of the SYN1 protein (p.Pro656Ser). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.056
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.27	T;.
FATHMM_MKL	Benign	0.18	N
LIST_S2	Benign	0.71	T;T
M_CAP	Benign	0.061	D
MetaRNN	Benign	0.14	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.4	L;L
MutationTaster	Benign	0.77	D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Benign	-1.6	N;N
REVEL	Benign	0.12
Sift	Benign	0.071	T;D
Sift4G	Uncertain	0.029	D;D
Polyphen		0.064	B;B
Vest4		0.19
MutPred		0.24		Loss of catalytic residue at P655 (P = 0.0165);Loss of catalytic residue at P655 (P = 0.0165);
MVP		0.48
MPC		2.6
ClinPred		0.80	D
GERP RS		3.8
Varity_R		0.11
gMVP		0.37

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: rs2057768744; hg19: chrX-47433417;