1-43447868-T-C

Position:

• chr1-43447868-T-C

Variant summary

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

The NM_001365999.1(SZT2):​c.9460T>C​(p.Ser3154Pro) variant causes a missense change. The variant allele was found at a frequency of 0.0000109 in 1,461,870 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. S3154C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000011 (0 hom.)
• Consequence: SZT2 NM_001365999.1 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.77

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-AS1 (HGNC:41225): (SZT2 antisense RNA 1)

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.9460T>C	p.Ser3154Pro	missense_variant	68/72	ENST00000634258.3	NP_001352928.1
SZT2	NM_015284.4	c.9289T>C	p.Ser3097Pro	missense_variant	67/71		NP_056099.3
SZT2-AS1	NR_046744.1	n.607A>G		non_coding_transcript_exon_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SZT2	ENST00000634258.3	c.9460T>C	p.Ser3154Pro	missense_variant	68/72	5	NM_001365999.1	ENSP00000489255.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251408 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135872

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000109 AC: 16 AN: 1461870 Hom.: 0 Cov.: 32 AF XY: 0.0000124 AC XY: 9 AN XY: 727244

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: 0.0000144

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000761 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 18 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Apr 11, 2023

- -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 24, 2022

The c.9289T>C (p.S3097P) alteration is located in exon 67 (coding exon 67) of the SZT2 gene. This alteration results from a T to C substitution at nucleotide position 9289, causing the serine (S) at amino acid position 3097 to be replaced by a proline (P). 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

Jan 14, 2022

This sequence change replaces serine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 3097 of the SZT2 protein (p.Ser3097Pro). This variant is not present in population databases (gnomAD no frequency). 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: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 588763). This variant has not been reported in the literature in individuals affected with SZT2-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.051	T
BayesDel_noAF	Benign	-0.17
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.14	T;.
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.52
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.91	D;D
M_CAP	Benign	0.0054	T
MetaRNN	Uncertain	0.49	T;T
MetaSVM	Benign	-0.82	T
MutationAssessor	Benign	1.0	L;.
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-1.7	.;N
Sift	Benign	0.13	.;T
Sift4G	Benign	0.25	T;T
Polyphen		0.94	P;D
Vest4		0.64
MVP		0.60
MPC		1.0
ClinPred		0.64	D
GERP RS		5.8
Varity_R		0.45
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: rs1271549438; hg19: chr1-43913539;