rs878855007

Positions:

• chr1-43424317-C-A
• chr1-43424317-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001365999.1(SZT2):​c.2356C>A​(p.Leu786Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 152,088 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 (★). Synonymous variant affecting the same amino acid position (i.e. L786L) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: SZT2 NM_001365999.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.50

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.27500683).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SZT2	NM_001365999.1	c.2356C>A	p.Leu786Met	missense_variant	16/72	ENST00000634258.3	NP_001352928.1
SZT2	NM_015284.4	c.2356C>A	p.Leu786Met	missense_variant	16/71		NP_056099.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SZT2	ENST00000634258.3	c.2356C>A	p.Leu786Met	missense_variant	16/72	5	NM_001365999.1	ENSP00000489255.1
SZT2	ENST00000562955.2	c.2356C>A	p.Leu786Met	missense_variant	16/71	5		ENSP00000457168.1
SZT2	ENST00000470139.1	n.1087C>A		non_coding_transcript_exon_variant	7/18	2		ENSP00000492726.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152088 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152088 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74282

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 01, 2021

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. 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: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with SZT2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces leucine with methionine at codon 786 of the SZT2 protein (p.Leu786Met). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and methionine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.0088	T
BayesDel_noAF	Benign	-0.25
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.12	T;.
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.79	T;T
M_CAP	Pathogenic	0.49	D
MetaRNN	Benign	0.28	T;T
MutationAssessor	Benign	1.5	L;L
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-0.41	.;N
Sift	Benign	0.13	.;T
Sift4G	Uncertain	0.025	D;D
Vest4		0.32
MVP		0.57
MPC		1.4
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.14
gMVP		0.54

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: rs878855007; hg19: chr1-43889988;