9-135770455-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>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000946 in 1,606,466 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: 𝑓 0.000072 (0 hom., cov: 34)
  • Exomes 𝑓: 0.000097 (0 hom.)
• Consequence: KCNT1 NM_020822.3 splice_region, intron
• Scores: Splicing: ADA: 0.0001098
• 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-T is Benign according to our data. Variant chr9-135770455-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 473362.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-135770455-C-T is described in Lovd as [Likely_benign].
• BS2: High AC in GnomAd at 11 AD gene.

Transcripts

RefSeq

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

Frequencies

GnomAD3 genomes AF: 0.0000723 AC: 11 AN: 152190 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000654

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000118

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000833 AC: 20 AN: 240194 Hom.: 0 AF XY: 0.0000770 AC XY: 10 AN XY: 129886

Gnomad AFR exome AF: 0.0000622

Gnomad AMR exome AF: 0.0000296

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000110

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000121

Gnomad OTH exome AF: 0.000515

GnomAD4 exome AF: 0.0000970 AC: 141 AN: 1454276 Hom.: 0 Cov.: 36 AF XY: 0.000102 AC XY: 74 AN XY: 722996

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000113

Gnomad4 ASJ exome AF: 0.0000392

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000118

Gnomad4 FIN exome AF: 0.0000191

Gnomad4 NFE exome AF: 0.000113

Gnomad4 OTH exome AF: 0.000117

GnomAD4 genome AF: 0.0000723 AC: 11 AN: 152190 Hom.: 0 Cov.: 34 AF XY: 0.0000538 AC XY: 4 AN XY: 74344

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000118

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000116 Hom.: 0

Bravo AF: 0.0000907

ClinVar

Significance: Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Benign:2

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 16, 2018	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. -
Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2021	- -

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

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 01, 2024

- -

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	7.2
Dann	Benign	0.89

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00011
dbscSNV1_RF	Benign	0.0
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: rs371287985; hg19: chr9-138662301;