rs371287985

chr9-135770455-C-Achr9-135770455-C-T

Variant summary

Our verdict is Benign. Variant got -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS2

The NM_020822.3(KCNT1):c.1769+8C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000172 in 1,454,278 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.000017 (0 hom.)
• Consequence: KCNT1 NM_020822.3 splice_region, intron
• Scores: Splicing: ADA: 0.00007431
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:5
• Conservation: PhyloP100: -0.00100

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 Benign. Variant got -16 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.78).
• BP6: Variant 9-135770455-C-A is Benign according to our data. Variant chr9-135770455-C-A is described in ClinVar as [Likely_benign]. Clinvar id is 386655.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAdExome at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNT1	NM_020822.3	c.1769+8C>A		splice_region_variant, intron_variant		ENST00000371757.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNT1	ENST00000371757.7	c.1769+8C>A		splice_region_variant, intron_variant		1	NM_020822.3	A2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD3 exomes AF: 0.0000208 AC: 5 AN: 240194 Hom.: 0 AF XY: 0.0000308 AC XY: 4 AN XY: 129886

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000465

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000172 AC: 25 AN: 1454278 Hom.: 0 Cov.: 36 AF XY: 0.0000180 AC XY: 13 AN XY: 722996

Gnomad4 AFR exome AF: 0.000330

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: 0.00000541

Gnomad4 OTH exome AF: 0.000133

GnomAD4 genome Cov.: 34

Bravo AF: 0.00000756

ClinVar

Significance: Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Mar 02, 2017

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Oct 16, 2023

- -

KCNT1-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 20, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Developmental and epileptic encephalopathy, 14 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Mar 15, 2022

- -

Autosomal dominant nocturnal frontal lobe epilepsy 5 Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Mar 15, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.78
Cadd	Benign	3.8
Dann	Benign	0.86

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000074
dbscSNV1_RF	Benign	0.0
SpliceAI score (max)		0.010		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: rs371287985; hg19: chr9-138662301;