chr22-20859329-TG-T

Position:

• chr22-20859329-TG-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_004782.4(SNAP29):​c.223delG​(p.Val75fs) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SNAP29 NM_004782.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.59

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]

SNAP29 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 22-20859329-TG-T is Pathogenic according to our data. Variant chr22-20859329-TG-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 224877.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr22-20859329-TG-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNAP29	NM_004782.4	c.223delG	p.Val75fs	frameshift_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.223delG	p.Val75fs	frameshift_variant	1/5	1	NM_004782.4	ENSP00000215730.6
PI4KA	ENST00000449120.1	c.-226delC		5_prime_UTR_variant	1/4	4		ENSP00000402437.1
SNAP29	ENST00000490458.1	n.253delG		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

CEDNIK syndrome Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Hadassah Hebrew University Medical Center	Jun 20, 2019	- -
Pathogenic, criteria provided, single submitter	research	Baylor-Hopkins Center for Mendelian Genomics, Johns Hopkins University School of Medicine	-	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Aug 01, 2005	- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs869312906; hg19: chr22-21213617;