7-120742602-G-C

Variant names:

• chr7-120742602-G-C
• NM_012281.3:c.1467G>C
• KCND2 p.Thr489Thr

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_012281.3(KCND2):​c.1467G>C​(p.Thr489Thr) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. T489T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCND2 NM_012281.3 splice_region, synonymous
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.00
• Publications: 0 publications found

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]

KCND2 Gene-Disease associations (from GenCC):

• KCND2-related neurodevelopmental disorder with or without seizures

  Inheritance: AD Classification: MODERATE Submitted by: G2P
• complex neurodevelopmental disorder

  Inheritance: AD Classification: LIMITED Submitted by: Illumina

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_012281.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCND2	NM_012281.3	MANE Select	c.1467G>C	p.Thr489Thr	splice_region synonymous	Exon 4 of 6	NP_036413.1	Q9NZV8

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCND2	ENST00000331113.9	TSL:1 MANE Select	c.1467G>C	p.Thr489Thr	splice_region synonymous	Exon 4 of 6	ENSP00000333496.4	Q9NZV8
	KCND2	ENST00000425288.1	TSL:4	c.222G>C	p.Thr74Thr	splice_region synonymous	Exon 3 of 5	ENSP00000415463.1	H7C445
	KCND2	ENST00000473190.1	TSL:4	n.282G>C		splice_region non_coding_transcript_exon	Exon 1 of 3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.30
CADD	Uncertain	24
DANN	Benign	0.94
PhyloP100		3.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.42		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.42		Position offset: 40
DS_DL_spliceai		0.24		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr7-120382656;