9-128617719-C-T

Variant names:

• chr9-128617719-C-T
• rs3750333
• NM_001130438.3:c.5437C>T

Variant summary

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

The NM_001130438.3(SPTAN1):​c.5437C>T​(p.Arg1813Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. R1813Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SPTAN1 NM_001130438.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.99
• Publications: 0 publications found

Genes affected

SPTAN1 (HGNC:11273): (spectrin alpha, non-erythrocytic 1) Spectrins are a family of filamentous cytoskeletal proteins that function as essential scaffold proteins that stabilize the plasma membrane and organize intracellular organelles. Spectrins are composed of alpha and beta dimers that associate to form tetramers linked in a head-to-head arrangement. This gene encodes an alpha spectrin that is specifically expressed in nonerythrocytic cells. The encoded protein has been implicated in other cellular functions including DNA repair and cell cycle regulation. Mutations in this gene are the cause of early infantile epileptic encephalopathy-5. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Sep 2010]

SPTAN1 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 5

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine
• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• infantile spasms

  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: MetaRNN computational evidence supports a deleterious effect, 0.803

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SPTAN1	NM_001130438.3	c.5437C>T	p.Arg1813Trp	missense_variant	Exon 42 of 57	ENST00000372739.7	NP_001123910.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SPTAN1	ENST00000372739.7	c.5437C>T	p.Arg1813Trp	missense_variant	Exon 42 of 57	1	NM_001130438.3	ENSP00000361824.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461832 Hom.: 0 Cov.: 39 AF XY: 0.00000138 AC XY: 1 AN XY: 727220

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111986

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy Uncertain:1

May 30, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with SPTAN1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with tryptophan at codon 1813 of the SPTAN1 protein (p.Arg1813Trp). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and tryptophan. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.54	D;.;.;.;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.80	D;D;D;D;D
MetaSVM	Benign	-0.32	T
MutationAssessor	Pathogenic	3.0	M;.;.;.;.
PhyloP100		4.0
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-6.8	D;.;D;.;.
REVEL	Uncertain	0.41
Sift	Pathogenic	0.0	D;.;D;.;.
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.73
MutPred		0.57		Loss of disorder (P = 0.0075);.;.;.;.;
MVP		0.69
MPC		1.9
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.82
gMVP		0.62
Mutation Taster		=20/80	disease causing

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

Other links and lift over

dbSNP: rs3750333; hg19: chr9-131379998;