NM_001032221.6:c.1709C>T

Variant names:

• chr9-127690781-C-T
• NM_001032221.6:c.1709C>T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP2 PP3_Moderate PP5_Moderate

The NM_001032221.6(STXBP1):​c.1709C>T​(p.Thr570Ile) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T570A) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: STXBP1 NM_001032221.6 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.37

Genes affected

STXBP1 (HGNC:11444): (syntaxin binding protein 1) This gene encodes a syntaxin-binding protein. The encoded protein appears to play a role in release of neurotransmitters via regulation of syntaxin, a transmembrane attachment protein receptor. Mutations in this gene have been associated with infantile epileptic encephalopathy-4. Alternatively spliced transcript variants have been described. [provided by RefSeq, Feb 2010]

PTRH1 (HGNC:27039): (peptidyl-tRNA hydrolase 1 homolog) Enables RNA binding activity. [provided by Alliance of Genome Resources, Apr 2022]

MIR3911 (HGNC:38962): (microRNA 3911) microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]

ENSG00000279571 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP2: Missense variant in the STXBP1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 106 curated pathogenic missense variants (we use a threshold of 10). The gene has 79 curated benign missense variants. Gene score misZ: 4.263 (above the threshold of 3.09). Trascript score misZ: 5.8379 (above the threshold of 3.09). GenCC associations: The gene is linked to intellectual disability, autosomal dominant non-syndromic intellectual disability, Dravet syndrome, undetermined early-onset epileptic encephalopathy, autism spectrum disorder, developmental and epileptic encephalopathy, West syndrome, atypical Rett syndrome, developmental and epileptic encephalopathy, 4.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.92
• PP5: Variant 9-127690781-C-T is Pathogenic according to our data. Variant chr9-127690781-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1326021.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
STXBP1	NM_001032221.6	c.1709C>T	p.Thr570Ile	missense_variant	Exon 19 of 19	ENST00000373299.5	NP_001027392.1
STXBP1	NM_003165.6	c.*23C>T		3_prime_UTR_variant	Exon 20 of 20	ENST00000373302.8	NP_003156.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
STXBP1	ENST00000373299.5	c.1709C>T	p.Thr570Ile	missense_variant	Exon 19 of 19	1	NM_001032221.6	ENSP00000362396.2
STXBP1	ENST00000373302.8	c.*23C>T		3_prime_UTR_variant	Exon 20 of 20	1	NM_003165.6	ENSP00000362399.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Nov 18, 2021

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Missense variants in this gene are often considered pathogenic (Stenson et al., 2014); Not observed at significant frequency in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: McCormick2021[Functional Study]) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	28
DANN	Uncertain	1.0
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.92	D
ClinPred		0.97	D
GERP RS		5.1

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr9-130453060;