16-30992834-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_052874.5(STX1B):c.854C>T(p.Thr285Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,460,358 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. T285T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: STX1B NM_052874.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.36

Genes affected

STX1B (HGNC:18539): (syntaxin 1B) The protein encoded by this gene belongs to a family of proteins thought to play a role in the exocytosis of synaptic vesicles. Vesicle exocytosis releases vesicular contents and is important to various cellular functions. For instance, the secretion of transmitters from neurons plays an important role in synaptic transmission. After exocytosis, the membrane and proteins from the vesicle are retrieved from the plasma membrane through the process of endocytosis. Mutations in this gene have been identified as one cause of fever-associated epilepsy syndromes. A possible link between this gene and Parkinson's disease has also been suggested. [provided by RefSeq, Jan 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, STX1B
• BP4: Computational evidence support a benign effect (MetaRNN=0.28985983).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
STX1B	NM_052874.5	c.854C>T	p.Thr285Met	missense_variant	10/10	ENST00000215095.11
STX1B	XM_017022893.2	c.836C>T	p.Thr279Met	missense_variant	10/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
STX1B	ENST00000215095.11	c.854C>T	p.Thr285Met	missense_variant	10/10	1	NM_052874.5	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460358 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726560

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: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Generalized epilepsy with febrile seizures plus, type 9 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Feb 06, 2022

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 285 of the STX1B protein (p.Thr285Met). 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with STX1B-related conditions. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.059	T
BayesDel_noAF	Benign	-0.15
Cadd	Uncertain	24
Dann	Uncertain	0.99
DEOGEN2	Benign	0.17	T
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Uncertain	0.93	D
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.29	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.9	L
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Benign	-0.62	N
REVEL	Benign	0.13
Sift	Benign	0.17	T
Sift4G	Benign	0.28	T
Polyphen		0.84	P
Vest4		0.44
MutPred		0.17		Loss of glycosylation at T285 (P = 0.0251);
MVP		0.30
MPC		1.5
ClinPred		0.74	D
GERP RS		4.6
Varity_R		0.12
gMVP		0.60

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: rs1410373910; hg19: chr16-31004155; COSMIC: COSV52680640; COSMIC: COSV52680640;