1-43437511-A-T

Variant names:

• chr1-43437511-A-T
• rs878855009
• NM_001365999.1:c.6290+3A>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001365999.1(SZT2):​c.6290+3A>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SZT2 NM_001365999.1 splice_region, intron
• Scores: Splicing: ADA: 0.9953
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.72
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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	c.6290+3A>T		splice_region_variant, intron_variant	Intron 44 of 71	ENST00000634258.3	NP_001352928.1
SZT2	NM_015284.4	c.6119+3A>T		splice_region_variant, intron_variant	Intron 43 of 70		NP_056099.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SZT2	ENST00000634258.3	c.6290+3A>T		splice_region_variant, intron_variant	Intron 44 of 71	5	NM_001365999.1	ENSP00000489255.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Dec 08, 2015

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 43 of the SZT2 mRNA. It does not directly change the encoded amino acid sequence of the SZT2 protein. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a SZT2-related disease. Algorithms developed to predict the effect of intronic changes on mRNA splicing suggest that this variant may alter mRNA splicing, but this prediction has not been confirmed by published transcriptional studies. In summary, this is a novel intronic change with uncertain impact on splicing. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.65
CADD	Benign	18
DANN	Benign	0.59
PhyloP100		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		0.74		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.74		Position offset: 15
DS_DL_spliceai		0.33		Position offset: -3

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

Other links and lift over

dbSNP: rs878855009; hg19: chr1-43903182;