Genetic Variant SZT2:p.Ser499Thr (chr1-43420983-G-C) – ACMG Classification: Likely_pathogenic (8 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2PM5PP3_Strong

The NM_001365999.1(SZT2):c.1496G>C(p.Ser499Thr) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000692 in 1,446,000 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S499I) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

SZT2
NM_001365999.1 missense, splice_region

Scores

Splicing: ADA: 1.000

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.68

Publications

0 publications found

Variant links:

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 Gene-Disease associations (from GenCC):

developmental and epileptic encephalopathy, 18
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P, Illumina
genetic developmental and epileptic encephalopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
undetermined early-onset epileptic encephalopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

SZT2 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-43420983-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 66998.Status of the report is no_assertion_criteria_provided, 0 stars.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SZT2	NM_001365999.1 link	c.1496G>C	p.Ser499Thr	missense_variant, splice_region_variant	Exon 10 of 72	ENST00000634258.3	NP_001352928.1
SZT2	NM_015284.4 link	c.1496G>C	p.Ser499Thr	missense_variant, splice_region_variant	Exon 10 of 71		NP_056099.3	Q5T011-5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SZT2	ENST00000634258.3 link	c.1496G>C	p.Ser499Thr	missense_variant, splice_region_variant	Exon 10 of 72	5	NM_001365999.1	ENSP00000489255.1		Q5T011-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.92e-7

AC:

AN:

1446000

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

719706

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

38022

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111668

Other (OTH)

AF:

0.00

AC:

AN:

60274

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.25

BayesDel_addAF

Uncertain

0.045

BayesDel_noAF

Benign

-0.17

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.14

T;.

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.88

D;D

M_CAP

Pathogenic

0.86

MetaRNN

Uncertain

0.63

D;D

MutationAssessor

Uncertain

2.0

M;M

PhyloP100

9.7

PrimateAI

Pathogenic

0.84

PROVEAN

Benign

-1.6

.;N

Sift

Uncertain

0.022

.;D

Sift4G

Uncertain

0.028

D;D

Vest4

0.46

MVP

0.74

MPC

1.2

GERP RS

5.2

Varity_R

0.17

gMVP

0.80

Mutation Taster

=24/76

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

1.0

SpliceAI score (max)

0.96

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.96

Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over