rs1553154643

Positions:

• chr1-43443774-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_001365999.1(SZT2):​c.8803C>T​(p.Arg2935Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,438 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R2935Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SZT2 NM_001365999.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 4.37

Genes affected

SZT2 (HGNC:29040): (SZT2 subunit of KICSTOR complex) The protein encoded by this gene is expressed in the brain, predominantly in the parietal and frontal cortex as well as in dorsal root ganglia. It is localized to the peroxisome, and is implicated in resistance to oxidative stress. It likely functions by increasing superoxide dismutase (SOD) activity, but itself has no direct SOD activity. Studies in mice show that this gene confers low seizure threshold, and may also enhance epileptogenesis. [provided by RefSeq, Jun 2011]

SZT2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SZT2. . Gene score misZ 2.5968 (greater than the threshold 3.09). Trascript score misZ 4.0086 (greater than threshold 3.09). GenCC has associacion of gene with undetermined early-onset epileptic encephalopathy, developmental and epileptic encephalopathy, 18, developmental and epileptic encephalopathy.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SZT2	NM_001365999.1	c.8803C>T	p.Arg2935Trp	missense_variant	62/72	ENST00000634258.3	NP_001352928.1
SZT2	NM_015284.4	c.8632C>T	p.Arg2878Trp	missense_variant	61/71		NP_056099.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SZT2	ENST00000634258.3	c.8803C>T	p.Arg2935Trp	missense_variant	62/72	5	NM_001365999.1	ENSP00000489255.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461438 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 727026

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: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Childhood epilepsy with centrotemporal spikes Pathogenic:1

Pathogenic, no assertion criteria provided

case-control

Bioinformatics Core, Luxembourg Center for Systems Biomedicine

Jan 01, 2017

CAADphred>15 -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 16, 2022

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 2878 of the SZT2 protein (p.Arg2878Trp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of SZT2-related conditions (PMID: 29358611). ClinVar contains an entry for this variant (Variation ID: 433095). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. 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	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.48	T;.
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Benign	0.018	T
MetaRNN	Uncertain	0.73	D;D
MetaSVM	Benign	-0.36	T
MutationAssessor	Benign	1.9	L;.
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-3.5	.;D
Sift	Uncertain	0.0020	.;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	.;D
Vest4		0.70
MutPred		0.45		.;Loss of disorder (P = 0.0091);
MVP		0.44
MPC		0.95
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.53
gMVP		0.56

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs1553154643; hg19: chr1-43909445; COSMIC: COSV65172908; COSMIC: COSV65172908;