rs948170691

Variant names:

• chr9-135786271-C-T
• rs948170691
• NM_020822.3:c.3252C>T

Variant summary

Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_Strong BP6_Moderate BS2

The NM_020822.3(KCNT1):​c.3252C>T​(p.Gly1084Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000745 in 1,609,920 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 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: KCNT1 NM_020822.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.134
• Publications: 0 publications found

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]

KCNT1 Gene-Disease associations (from GenCC):

• childhood-onset epilepsy syndrome

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 14

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• malignant migrating partial seizures of infancy

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, Orphanet
• autosomal dominant nocturnal frontal lobe epilepsy 5

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal dominant nocturnal frontal lobe epilepsy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Benign. The variant received -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.83).
• BP6: Variant 9-135786271-C-T is Benign according to our data. Variant chr9-135786271-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 583108.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS2: High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNT1	NM_020822.3	c.3252C>T	p.Gly1084Gly	synonymous_variant	Exon 29 of 31	ENST00000371757.7	NP_065873.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNT1	ENST00000371757.7	c.3252C>T	p.Gly1084Gly	synonymous_variant	Exon 29 of 31	1	NM_020822.3	ENSP00000360822.2

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152150 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00 AC: 0 AN: 229518 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000549 AC: 8 AN: 1457770 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 725066

African (AFR) AF: 0.000179 AC: 6 AN: 33442

American (AMR) AF: 0.00 AC: 0 AN: 44560

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26022

East Asian (EAS) AF: 0.00 AC: 0 AN: 39586

South Asian (SAS) AF: 0.00 AC: 0 AN: 85848

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5740

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111024

Other (OTH) AF: 0.0000166 AC: 1 AN: 60132

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152150 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74336

African (AFR) AF: 0.0000965 AC: 4 AN: 41450

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5180

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 314

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67984

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000340

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Apr 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.83
CADD	Benign	0.91
DANN	Benign	0.59
PhyloP100		-0.13

Splicing

Name	Calibrated prediction	Score	Prediction
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

Other links and lift over

dbSNP: rs948170691; hg19: chr9-138678117;