9-135779438-A-G

Variant names:

• chr9-135779438-A-G
• rs1554778379
• NM_020822.3:c.2809A>G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4 BP6

The NM_020822.3(KCNT1):​c.2809A>G​(p.Ser937Gly) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,440 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNT1 NM_020822.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 5.14

Genes affected

KCNT1 (HGNC:18865): (potassium sodium-activated channel subfamily T member 1) Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. This gene encodes a sodium-activated potassium channel subunit which is thought to function in ion conductance and developmental signaling pathways. Mutations in this gene cause the early-onset epileptic disorders, malignant migrating partial seizures of infancy and autosomal dominant nocturnal frontal lobe epilepsy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2791206).
• BP6: Variant 9-135779438-A-G is Benign according to our data. Variant chr9-135779438-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 435564.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3	c.2809A>G	p.Ser937Gly	missense_variant	Exon 24 of 31	ENST00000371757.7	NP_065873.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7	c.2809A>G	p.Ser937Gly	missense_variant	Exon 24 of 31	1	NM_020822.3	ENSP00000360822.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461440 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727024

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Uncertain:1

Aug 05, 2016

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

May 20, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 36499459) -

Developmental and epileptic encephalopathy, 14;C3554306:Autosomal dominant nocturnal frontal lobe epilepsy 5 Benign:1

Feb 23, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.39
CADD	Uncertain	24
DANN	Uncertain	0.98
DEOGEN2	Benign	0.069	.;.;.;.;.;.;.;.;T;.
Eigen	Benign	-0.22
Eigen_PC	Benign	-0.080
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Benign	0.69	T;T;T;T;T;T;T;T;T;T
M_CAP	Benign	0.045	D
MetaRNN	Benign	0.28	T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.78	T
MutationAssessor	Benign	0.69	.;.;.;.;.;.;.;.;N;.
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-2.5	N;.;N;N;.;.;.;.;N;N
REVEL	Benign	0.17
Sift	Uncertain	0.0070	D;.;T;D;.;.;.;.;T;T
Sift4G	Benign	0.38	T;T;T;T;T;T;T;T;T;T
Polyphen		0.0010	.;.;.;.;.;.;.;.;B;.
Vest4		0.45
MutPred		0.34		.;.;.;.;.;.;Loss of phosphorylation at S918 (P = 0.0373);Loss of phosphorylation at S918 (P = 0.0373);Loss of phosphorylation at S918 (P = 0.0373);.;
MVP		0.67
MPC		0.58
ClinPred		0.71	D
GERP RS		3.8
Varity_R		0.21
gMVP		0.78

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1554778379; hg19: chr9-138671284;