chr9-128612121-G-C

Position:

• chr9-128612121-G-C

Variant summary

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

The NM_001130438.3(SPTAN1):​c.4918G>C​(p.Ala1640Pro) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SPTAN1 NM_001130438.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.55

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]

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), SPTAN1. . Gene score misZ 5.523 (greater than the threshold 3.09). Trascript score misZ 7.9287 (greater than threshold 3.09). GenCC has associacion of gene with developmental and epileptic encephalopathy, 5, developmental and epileptic encephalopathy, West syndrome.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPTAN1	NM_001130438.3	c.4918G>C	p.Ala1640Pro	missense_variant	39/57	ENST00000372739.7	NP_001123910.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPTAN1	ENST00000372739.7	c.4918G>C	p.Ala1640Pro	missense_variant	39/57	1	NM_001130438.3	ENSP00000361824	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early infantile epileptic encephalopathy with suppression bursts Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 17, 2023

This variant has not been reported in the literature in individuals affected with SPTAN1-related conditions. This sequence change replaces alanine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 1640 of the SPTAN1 protein (p.Ala1640Pro). This variant is not present in population databases (gnomAD no frequency). ClinVar contains an entry for this variant (Variation ID: 461227). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SPTAN1 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Benign	0.30	T;.;.;.;.
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D
M_CAP	Benign	0.010	T
MetaRNN	Uncertain	0.59	D;D;D;D;D
MetaSVM	Benign	-0.65	T
MutationAssessor	Uncertain	2.2	M;.;.;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	-2.0	N;.;N;.;.
REVEL	Uncertain	0.31
Sift	Benign	0.14	T;.;T;.;.
Sift4G	Benign	0.25	T;T;T;T;T
Polyphen		1.0	D;.;D;D;.
Vest4		0.63
MutPred		0.60		Loss of stability (P = 0.0306);.;.;.;.;
MVP		0.67
MPC		2.0
ClinPred		0.87	D
GERP RS		5.9
Varity_R		0.59
gMVP		0.75

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: rs1554759970; hg19: chr9-131374400;