rs779262121

Variant names:

• chr9-135792132-C-G
• NM_020822.3:c.3679C>G

Your query was ambiguous. Multiple possible variants found:

• chr9-135792132-C-G
• chr9-135792132-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_020822.3(KCNT1):​c.3679C>G​(p.Pro1227Ala) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P1227P) has been classified as Benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: KCNT1 NM_020822.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 3.78

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]

LOC107987140 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.26606923).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3	c.3679C>G	p.Pro1227Ala	missense_variant	Exon 31 of 31	ENST00000371757.7	NP_065873.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7	c.3679C>G	p.Pro1227Ala	missense_variant	Exon 31 of 31	1	NM_020822.3	ENSP00000360822.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Dec 20, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: KCNT1 c.3679C>G (p.Pro1227Ala) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 241640 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.3679C>G in individuals affected with Developmental And Epileptic Encephalopathy, 14 and no experimental evidence demonstrating its impact on protein function have been reported. One submitter has reported clinical-significance assessments for this variant to ClinVar after 2014 and has classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Jul 14, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 1227 of the KCNT1 protein (p.Pro1227Ala). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with KCNT1-related conditions. 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) performed at Invitae indicates that this missense variant is not expected to disrupt KCNT1 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	Benign	0.069
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	20
DANN	Benign	0.90
DEOGEN2	Benign	0.049	.;.;.;.;.;.;.;.;T;.
Eigen	Benign	0.043
Eigen_PC	Benign	0.10
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.86	D;D;D;D;D;D;D;D;D;D
M_CAP	Benign	0.031	D
MetaRNN	Benign	0.27	T;T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.0	.;.;.;.;.;.;.;.;L;.
PrimateAI	Benign	0.45	T
PROVEAN	Benign	-1.4	.;.;N;.;.;.;.;.;.;N
REVEL	Benign	0.051
Sift	Benign	0.12	.;.;T;.;.;.;.;.;.;T
Sift4G	Benign	0.14	T;T;T;T;T;T;T;T;T;T
Vest4		0.56
MVP		0.47
MPC		0.088
ClinPred		0.30	T
GERP RS		4.7
Varity_R		0.081
gMVP		0.26

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr9-138683978;