7-120274633-A-T

Variant names:

• chr7-120274633-A-T
• NM_012281.3:c.1A>T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PVS1_Supporting PM2

The NM_012281.3(KCND2):​c.1A>T​(p.Met1?) variant causes a initiator codon 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. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCND2 NM_012281.3 initiator_codon
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.40

Genes affected

KCND2 (HGNC:6238): (potassium voltage-gated channel subfamily D member 2) 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 mediates a rapidly inactivating, A-type outward potassium current which is not under the control of the N terminus as it is in Shaker channels. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PVS1: Start lost variant, no pathogenic variants between lost start and next in-frame start position. Next in-frame start position is after 20 codons. Genomic position: 120274690. Lost 0.031 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCND2	NM_012281.3	c.1A>T	p.Met1?	initiator_codon_variant	Exon 1 of 6	ENST00000331113.9	NP_036413.1
KCND2	XM_047420346.1	c.1A>T	p.Met1?	initiator_codon_variant	Exon 2 of 7		XP_047276302.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCND2	ENST00000331113.9	c.1A>T	p.Met1?	initiator_codon_variant	Exon 1 of 6	1	NM_012281.3	ENSP00000333496.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Early myoclonic encephalopathy Uncertain:1

Dec 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects the initiator methionine of the KCND2 mRNA. The next in-frame methionine is located at codon 20. This variant is not present in population databases (gnomAD no frequency). Disruption of the initiator codon has been observed in individual(s) with clinical features of developmental and epileptic encephalopathy (internal data). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.43
CADD	Uncertain	24
DANN	Benign	0.97
DEOGEN2	Benign	0.21	T
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.41	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.96	D
PROVEAN	Benign	-1.3	N
REVEL	Pathogenic	0.81
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.97	D
Vest4		0.71
MutPred		0.92		Loss of disorder (P = 0.0741);
MVP		0.92
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.88
gMVP		0.56

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: chr7-119914687;