rs1217571134

Variant names:

• chr1-111982281-T-C
• rs1217571134
• NM_001378969.1:c.446A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_001378969.1(KCND3):​c.446A>G​(p.Asp149Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,876 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. D149D) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCND3 NM_001378969.1 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 7.67
• Publications: 1 publications found

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]

KCND3 Gene-Disease associations (from GenCC):

• neurodevelopmental disorder

  Inheritance: AD Classification: STRONG Submitted by: G2P
• spinocerebellar ataxia type 19/22

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, Ambry Genetics
• Brugada syndrome 9

  Inheritance: AD Classification: LIMITED Submitted by: Genomics England PanelApp
• Brugada syndrome 1

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the KCND3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 20 curated pathogenic missense variants (we use a threshold of 10). The gene has 4 curated benign missense variants. Gene score misZ: 3.8545 (above the threshold of 3.09). Trascript score misZ: 4.8782 (above the threshold of 3.09). GenCC associations: The gene is linked to spinocerebellar ataxia type 19/22, neurodevelopmental disorder, Brugada syndrome 1, Brugada syndrome 9.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.798

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCND3	NM_001378969.1	c.446A>G	p.Asp149Gly	missense_variant	Exon 2 of 8	ENST00000302127.5	NP_001365898.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCND3	ENST00000302127.5	c.446A>G	p.Asp149Gly	missense_variant	Exon 2 of 8	5	NM_001378969.1	ENSP00000306923.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251310 AF XY: 0.00000736

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461876 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727244

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Nov 08, 2016

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Jul 28, 2021

AiLife Diagnostics, AiLife Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype Uncertain:1

Nov 14, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D149G variant (also known as c.446A>G), located in coding exon 1 of the KCND3 gene, results from an A to G substitution at nucleotide position 446. The aspartic acid at codon 149 is replaced by glycine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Spinocerebellar ataxia type 19/22 Uncertain:1

Jun 05, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals with KCND3-related conditions. ClinVar contains an entry for this variant (Variation ID: 447628). This variant is not present in population databases (ExAC no frequency). This sequence change replaces aspartic acid with glycine at codon 149 of the KCND3 protein (p.Asp149Gly). The aspartic acid residue is highly conserved and there is a moderate physicochemical difference between aspartic acid and glycine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.55	.;D;.
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.88	.;D;D
M_CAP	Pathogenic	0.35	D
MetaRNN	Pathogenic	0.80	D;D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Uncertain	2.8	M;M;M
PhyloP100		7.7
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-4.2	D;D;D
REVEL	Pathogenic	0.79
Sift	Uncertain	0.028	D;D;D
Sift4G	Uncertain	0.041	D;D;D
Polyphen		0.013	.;B;.
Vest4		0.79
MutPred		0.30		Loss of stability (P = 0.025);Loss of stability (P = 0.025);Loss of stability (P = 0.025);
MVP		0.98
MPC		1.8
ClinPred		0.93	D
GERP RS		5.6
Varity_R		0.55
gMVP		0.83
Mutation Taster		=10/90	disease causing

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

Other links and lift over

dbSNP: rs1217571134; hg19: chr1-112524903;