rs1556861785

chrX-47619379-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_006950.3(SYN1):c.350T>C(p.Leu117Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. L117L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 22)
• Consequence: SYN1 NM_006950.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.93

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_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.981

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYN1	NM_006950.3	c.350T>C	p.Leu117Pro	missense_variant	1/13	ENST00000295987.13
SYN1	NM_133499.2	c.350T>C	p.Leu117Pro	missense_variant	1/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYN1	ENST00000295987.13	c.350T>C	p.Leu117Pro	missense_variant	1/13	2	NM_006950.3	P3
SYN1	ENST00000340666.5	c.350T>C	p.Leu117Pro	missense_variant	1/13	1		A1
SYN1	ENST00000639776.1	c.11T>C	p.Leu4Pro	missense_variant	1/6	3

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 01, 2022

ClinVar contains an entry for this variant (Variation ID: 465096). 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 leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 117 of the SYN1 protein (p.Leu117Pro). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
Cadd	Pathogenic	32
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D;.
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	-0.13	T
MutationAssessor	Uncertain	2.3	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.94	D
PROVEAN	Pathogenic	-5.4	D;D
REVEL	Pathogenic	0.74
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.91
MutPred		0.87		Gain of sheet (P = 0.0043);Gain of sheet (P = 0.0043);
MVP		0.95
MPC		2.1
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.98
gMVP		0.98

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: rs1556861785; hg19: chrX-47478778;