1-111776099-A-G

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 1P and 6B. PP2 BP4_Moderate BS2

The NM_001378969.1(KCND3):c.1946T>C(p.Val649Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,894 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: KCND3 NM_001378969.1 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 8.93

Genes affected

KCND3 (HGNC:6239): (potassium voltage-gated channel subfamily D member 3) Voltage-gated potassium (Kv) 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, shal-related subfamily, members of which form voltage-activated A-type potassium ion channels and are prominent in the repolarization phase of the action potential. This member includes two isoforms with different sizes, which are encoded by alternatively spliced transcript variants of this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• PP2: Missense variant where missense usually causes diseases, KCND3
• BP4: Computational evidence support a benign effect (MetaRNN=0.10150954).
• BS2: High AC in GnomAdExome at 6 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCND3	NM_001378969.1	c.1946T>C	p.Val649Ala	missense_variant	8/8	ENST00000302127.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCND3	ENST00000302127.5	c.1946T>C	p.Val649Ala	missense_variant	8/8	5	NM_001378969.1	P3
KCND3	ENST00000315987.6	c.1946T>C	p.Val649Ala	missense_variant	8/8	1		P3
KCND3	ENST00000369697.5	c.1889T>C	p.Val630Ala	missense_variant	6/6	1		A1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000239 AC: 6 AN: 251194 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135800

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000173

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461894 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000134

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Spinocerebellar ataxia type 19/22;C4225340:Brugada syndrome 9 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Sep 24, 2021

- -

Spinocerebellar ataxia type 19/22 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 10, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 649 of the KCND3 protein (p.Val649Ala). This variant is present in population databases (rs760907112, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with KCND3-related conditions. ClinVar contains an entry for this variant (Variation ID: 1027158). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Benign	-0.041	T
BayesDel_noAF	Uncertain	-0.030
Cadd	Uncertain	24
Dann	Uncertain	1.0
Eigen	Benign	0.071
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Benign	0.044	D
MetaRNN	Benign	0.10	T;T;T
MetaSVM	Uncertain	0.21	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.85	N;N;N
REVEL	Uncertain	0.35
Sift	Uncertain	0.010	D;D;D
Sift4G	Benign	0.16	T;T;T
Polyphen		0.0080	.;B;.
Vest4		0.32
MutPred		0.21		.;Loss of stability (P = 0.0198);.;
MVP		0.49
MPC		0.41
ClinPred		0.22	T
GERP RS		5.6
Varity_R		0.13
gMVP		0.65

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs760907112; hg19: chr1-112318721;