rs183022730

chr9-135750122-C-T

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_020822.3(KCNT1):c.279C>T(p.Asn93=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000508 in 1,613,808 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 Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000049 (0 hom.)
• Consequence: KCNT1 NM_020822.3 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:5
• Conservation: PhyloP100: -0.829

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 -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.54).
• BP6: Variant 9-135750122-C-T is Benign according to our data. Variant chr9-135750122-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 512972.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr9-135750122-C-T is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=-0.829 with no splicing effect.
• BS1: Variant frequency is greater than expected in population amr. gnomad4_exome allele frequency = 0.0000493 (72/1461554) while in subpopulation AMR AF= 0.000738 (33/44712). AF 95% confidence interval is 0.00054. There are 0 homozygotes in gnomad4_exome. There are 39 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck.
• BS2: High AC in GnomAd at 9 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNT1	NM_020822.3	c.279C>T	p.Asn93=	synonymous_variant	3/31	ENST00000371757.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNT1	ENST00000371757.7	c.279C>T	p.Asn93=	synonymous_variant	3/31	1	NM_020822.3	A2

Frequencies

GnomAD3 genomes AF: 0.0000592 AC: 9 AN: 152136 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000262

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000386

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.0000997 AC: 25 AN: 250872 Hom.: 0 AF XY: 0.0000810 AC XY: 11 AN XY: 135828

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000550

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000177

Gnomad OTH exome AF: 0.000490

GnomAD4 exome AF: 0.0000493 AC: 72 AN: 1461554 Hom.: 0 Cov.: 31 AF XY: 0.0000536 AC XY: 39 AN XY: 727072

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.000738

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000176

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000188

Gnomad4 NFE exome AF: 0.0000207

Gnomad4 OTH exome AF: 0.0000994

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152254 Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5 AN XY: 74444

Gnomad4 AFR AF: 0.0000481

Gnomad4 AMR AF: 0.000261

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000386

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.0000762 Hom.: 0

Bravo AF: 0.0000793

Asia WGS AF: 0.000289 AC: 1 AN: 3478

EpiCase AF: 0.00

EpiControl AF: 0.0000593

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

Nov 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

Jan 08, 2024

- -

Inborn genetic diseases Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 29, 2017

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

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	-0.54
Cadd	Benign	11
Dann	Benign	0.71

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: rs183022730; hg19: chr9-138641968; COSMIC: COSV53699561; COSMIC: COSV53699561;