22-20859136-A-G

Position:

• chr22-20859136-A-G

Variant summary

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

The NM_004782.4(SNAP29):​c.26A>G​(p.Asn9Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000275 in 1,455,896 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 (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000027 (0 hom.)
• Consequence: SNAP29 NM_004782.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.41

Genes affected

SNAP29 (HGNC:11133): (synaptosome associated protein 29) This gene, a member of the SNAP25 gene family, encodes a protein involved in multiple membrane trafficking steps. Two other members of this gene family, SNAP23 and SNAP25, encode proteins that bind a syntaxin protein and mediate synaptic vesicle membrane docking and fusion to the plasma membrane. The protein encoded by this gene binds tightly to multiple syntaxins and is localized to intracellular membrane structures rather than to the plasma membrane. While the protein is mostly membrane-bound, a significant fraction of it is found free in the cytoplasm. Use of multiple polyadenylation sites has been noted for this gene. [provided by RefSeq, Jul 2008]

PI4KA (HGNC:8983): (phosphatidylinositol 4-kinase alpha) This gene encodes a phosphatidylinositol (PI) 4-kinase which catalyzes the first committed step in the biosynthesis of phosphatidylinositol 4,5-bisphosphate. The mammalian PI 4-kinases have been classified into two types, II and III, based on their molecular mass, and modulation by detergent and adenosine. The protein encoded by this gene is a type III enzyme that is not inhibited by adenosine. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Apr 2018]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3227429).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNAP29	NM_004782.4	c.26A>G	p.Asn9Ser	missense_variant	1/5	ENST00000215730.12	NP_004773.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNAP29	ENST00000215730.12	c.26A>G	p.Asn9Ser	missense_variant	1/5	1	NM_004782.4	ENSP00000215730	P1
PI4KA	ENST00000449120.1	c.-32T>C		5_prime_UTR_variant	1/4	4		ENSP00000402437
SNAP29	ENST00000490458.1	n.56A>G		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000174 AC: 4 AN: 229312 Hom.: 0 AF XY: 0.0000239 AC XY: 3 AN XY: 125712

Gnomad AFR exome AF: 0.0000718

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000342

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000200

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000275 AC: 40 AN: 1455896 Hom.: 0 Cov.: 32 AF XY: 0.0000221 AC XY: 16 AN XY: 723844

Gnomad4 AFR exome AF: 0.0000897

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000117

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000306

Gnomad4 OTH exome AF: 0.0000333

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000332 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 17, 2022

The c.26A>G (p.N9S) alteration is located in exon 1 (coding exon 1) of the SNAP29 gene. This alteration results from a A to G substitution at nucleotide position 26, causing the asparagine (N) at amino acid position 9 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 27, 2022

This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 9 of the SNAP29 protein (p.Asn9Ser). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with SNAP29-related conditions. 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: "Possibly Damaging"; Align-GVGD: "Class C15"). 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	Benign	0.33
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.39
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.27	T
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D
M_CAP	Uncertain	0.099	D
MetaRNN	Benign	0.32	T
MetaSVM	Benign	-0.63	T
MutationAssessor	Uncertain	2.4	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.79	T
PROVEAN	Uncertain	-3.4	D
REVEL	Benign	0.27
Sift	Uncertain	0.011	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.95	P
Vest4		0.38
MutPred		0.47		Gain of phosphorylation at N9 (P = 0.005);
MVP		0.70
MPC		0.22
ClinPred		0.94	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.43
gMVP		0.66

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: rs775931172; hg19: chr22-21213424;