chr1-110673482-G-A

Position:

• chr1-110673482-G-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_002232.5(KCNA3):​c.1328C>T​(p.Thr443Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/20 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: KCNA3 NM_002232.5 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 10.0

Genes affected

KCNA3 (HGNC:6221): (potassium voltage-gated channel subfamily A member 3) 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. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. It plays an essential role in T-cell proliferation and activation. This gene appears to be intronless and it is clustered together with KCNA2 and KCNA10 genes on chromosome 1. [provided by RefSeq, Jul 2008]

KCNA3 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 1-110673482-G-A is Pathogenic according to our data. Variant chr1-110673482-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2500323.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCNA3	NM_002232.5	c.1328C>T	p.Thr443Ile	missense_variant	1/1	ENST00000369769.4	NP_002223.3
KCNA3	NR_109845.2	n.-28C>T		upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNA3	ENST00000369769.4	c.1328C>T	p.Thr443Ile	missense_variant	1/1	6	NM_002232.5	ENSP00000358784.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

KCNA3-associated developmental and epileptic encephalopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

Institute of Human Genetics, University of Leipzig Medical Center

Feb 14, 2023

This variant was identified as de novo (maternity and paternity confirmed). Criteria applied: PS3, PS2_MOD, PM2_SUP, PP3 -

Neurodevelopmental disorder Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Sep 22, 2024

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely pathogenic. Following criteria are met: 0105 - The mechanism of disease for this gene is not clearly established. This gene is associated with neurodevelopmental disorder, MONDO:0700092, KCNA3-related. (I) 0107 - This gene is associated with autosomal dominant disease (personal communication). (I) 0200 - Variant is predicted to result in a missense amino acid change from threonine to isoleucine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0602 - Variant is located in a hotspot region or cluster of pathogenic variants from residues 431 to 478 (DECIPHER, Personal communications). (SP) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0802 - This variant has moderate previous evidence of pathogenicity in an unrelated individual. This variant has been identified in a de novo heterozygous individual with developmental and epileptic encephalopathy (Personal communications). (SP) 0905 - No published segregation evidence has been identified for this variant. (I) 1002 - This variant has moderate functional evidence supporting abnormal protein function. This variant causes absent Kv1.3 channel current, and when co-transfected it suppresses currents carried by wild-type Kv1.3 subunits (Personal communications). (SP) 1203 - This variant has been shown to be de novo in the proband (parental status confirmed) (by trio analysis). (SP) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.32	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-5.4	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0030	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.90		Loss of glycosylation at T443 (P = 0.074);
MVP		0.97
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.87
gMVP		1.0

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-111216104;