19-7637154-C-T

Position:

• chr19-7637154-C-T

Variant summary

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

The NM_006949.4(STXBP2):​c.5C>T​(p.Ala2Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000184 in 1,088,992 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A2A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000018 (0 hom.)
• Consequence: STXBP2 NM_006949.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.21

Genes affected

STXBP2 (HGNC:11445): (syntaxin binding protein 2) This gene encodes a member of the STXBP/unc-18/SEC1 family. The encoded protein is involved in intracellular trafficking, control of SNARE (soluble NSF attachment protein receptor) complex assembly, and the release of cytotoxic granules by natural killer cells. Mutations in this gene are associated with familial hemophagocytic lymphohistiocytosis. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene. [provided by RefSeq, Jan 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
STXBP2	NM_006949.4	c.5C>T	p.Ala2Val	missense_variant	1/19	ENST00000221283.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
STXBP2	ENST00000221283.10	c.5C>T	p.Ala2Val	missense_variant	1/19	1	NM_006949.4	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000184 AC: 2 AN: 1088992 Hom.: 0 Cov.: 31 AF XY: 0.00000194 AC XY: 1 AN XY: 514414

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: 0.0000340

Gnomad4 NFE exome AF: 0.00000109

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial hemophagocytic lymphohistiocytosis 5 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 11, 2022

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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 641714). This variant has not been reported in the literature in individuals affected with STXBP2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 2 of the STXBP2 protein (p.Ala2Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.69
BayesDel_addAF	Uncertain	0.087	D
BayesDel_noAF	Benign	-0.11
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.031	.;.;T;.
Eigen	Benign	-0.11
Eigen_PC	Benign	-0.024
FATHMM_MKL	Uncertain	0.78	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Uncertain	0.59	D;D;D;D
MetaSVM	Benign	-0.52	T
MutationAssessor	Uncertain	2.4	.;M;M;M
MutationTaster	Benign	0.96	D;D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-0.89	.;N;N;N
REVEL	Uncertain	0.41
Sift	Uncertain	0.0030	.;D;D;D
Sift4G	Uncertain	0.010	D;D;D;D
Polyphen		0.47, 0.60	.;.;P;P
Vest4		0.18, 0.18, 0.20
MutPred		0.58		Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);Loss of helix (P = 0.079);
MVP		0.83
MPC		0.71
ClinPred		0.94	D
GERP RS		3.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.16
gMVP		0.47

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1599386139; hg19: chr19-7702040;