19-7642081-T-C

Variant names:

• chr19-7642081-T-C
• rs121918541
• NM_006949.4:c.626T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_006949.4(STXBP2):​c.626T>C​(p.Leu209Pro) variant causes a missense change. 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L209Q) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: STXBP2 NM_006949.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 5.88
• Publications: 3 publications found

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]

STXBP2 Gene-Disease associations (from GenCC):

• familial hemophagocytic lymphohistiocytosis 5

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: Ambry Genetics, ClinGen, Labcorp Genetics (formerly Invitae)
• hereditary hemophagocytic lymphohistiocytosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• microvillus inclusion disease

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ENSG00000268400 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006949.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	STXBP2	NM_006949.4	MANE Select	c.626T>C	p.Leu209Pro	missense	Exon 8 of 19	NP_008880.2
	STXBP2	NM_001272034.2		c.659T>C	p.Leu220Pro	missense	Exon 8 of 19	NP_001258963.1
	STXBP2	NM_001127396.3		c.617T>C	p.Leu206Pro	missense	Exon 8 of 19	NP_001120868.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	STXBP2	ENST00000221283.10	TSL:1 MANE Select	c.626T>C	p.Leu209Pro	missense	Exon 8 of 19	ENSP00000221283.4
	STXBP2	ENST00000414284.6	TSL:1	c.617T>C	p.Leu206Pro	missense	Exon 8 of 19	ENSP00000409471.1
	STXBP2	ENST00000597068.5	TSL:1	n.626T>C		non_coding_transcript_exon	Exon 8 of 19	ENSP00000471327.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

Alfa AF: 0.00000525 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS, FAMILIAL, 5, WITHOUT MICROVILLUS INCLUSION DISEASE Pathogenic:1

Oct 01, 2009

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

not specified Uncertain:1

Jun 27, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: STXBP2 c.626T>C (p.Leu209Pro) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function all suggest that this variant is likely to be disruptive. The variant was absent in 250928 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.626T>C has been observed in a compound heterozygous individual affected with Familial Hemophagocytic Lymphohistiocytosis (e.g. zur Stadt_2009, Rohr_2010). These data do not allow any conclusion about variant significance. At least one publication reports experimental evidence evaluating an impact on protein function, however, does not allow convincing conclusions about the variant effect (e.g. zur Stadt_2009). The following publications have been ascertained in the context of this evaluation (PMID: 20823128, 19804848). ClinVar contains an entry for this variant (Variation ID: 7861). Based on the evidence outlined above, the variant was classified as uncertain significance.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Uncertain	0.36
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Benign	0.85	T
M_CAP	Pathogenic	0.41	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Pathogenic	3.6	H
PhyloP100		5.9
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-6.2	D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.95		Gain of disorder (P = 0.0122)
MVP		0.94
MPC		1.1
ClinPred		1.0	D
GERP RS		3.3
Varity_R		0.99
gMVP		0.98
Mutation Taster		=5/95	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		2.0
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

Other links and lift over

dbSNP: rs121918541; hg19: chr19-7706967;