Variant chr7-66638394-G-A details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_153033.5(KCTD7):c.456G>A(p.Val152Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,892 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

KCTD7
NM_153033.5 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 0.190

Variant links:

Genes affected

KCTD7 (HGNC:21957): (potassium channel tetramerization domain containing 7) This gene encodes a member of the potassium channel tetramerization domain-containing protein family. Family members are identified on a structural basis and contain an amino-terminal domain similar to the T1 domain present in the voltage-gated potassium channel. Mutations in this gene have been associated with progressive myoclonic epilepsy-3. Alternative splicing results in multiple transcript variants.[provided by RefSeq, Jan 2011]

KCTD7 links:

ENSG00000284461 (HGNC:):

ENSG00000284461 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
KCTD7	NM_153033.5 link	c.456G>A	p.Val152Val	synonymous_variant	3/4	ENST00000639828.2	NP_694578.1	Q96MP8-1A0A024RDN7
KCTD7	NM_001167961.2 link	c.456G>A	p.Val152Val	synonymous_variant	3/5		NP_001161433.1	Q96MP8-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCTD7	ENST00000639828.2 link	c.456G>A	p.Val152Val	synonymous_variant	3/4	2	NM_153033.5	ENSP00000492240.1		Q96MP8-1
ENSG00000284461	ENST00000503687.2 link	n.286G>A		non_coding_transcript_exon_variant	2/13	2		ENSP00000421074.1		E9PHB8

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251394

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135864

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000867

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:

0.00000342

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Progressive myoclonic epilepsy type 3

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 11, 2024	This sequence change affects codon 152 of the KCTD7 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the KCTD7 protein. This variant is present in population databases (rs796052686, gnomAD 0.009%). This variant has been observed in individual(s) with clinical features of progressive myoclonic epilepsy (PMID: 31160820, 33970744; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 206004). Studies have shown that this variant alters KCTD7 gene expression (PMID: 31160820, 33970744). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Undiagnosed Diseases Network, NIH	Aug 22, 2017	Heterozygous c.280C>T (p.R94W) likely pathogenic variant and c.456G>A (p.V152V) variant of unknown clinical significance in the KCTD7 gene were detected by exome sequencing and confirmed by Sanger sequencing this individual and her similarly affected younger brother. The c.280C>T (p.R94W) likely pathogenic variant has been previously reported in the homozygous state in two apparently unrelated Turkish patients [PMID 22693283, 22606975]. The potential pathogenicity of the variant is also supported by a recent functional study [PMID 27742667]. The c.456G>A (p.V152V) variant was predicted to affect splicing by in silico modeling. This effect on splicing was confirmed by RNA sequencing which showed evidence of a novel splice donor site that prematurely terminates exon 3 of KCTD7 in patient samples. Splicing effect was also confirmed by Sanger sequencing of amplified cDNA corresponding to KCTD7 exons 2-4 which showed two discrete bands in patients compared to one band in unrelated controls [Zastrow et al., ASHG 2017]. Whole exome sequencing analysis and Sanger analysis showed that the father is heterozygous for c.280C>T (p.R94W) and the mother is heterozygous for c.456G>A (p.V152V), indicating the two variants are in trans in this individual and her brother. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Aug 24, 2017

A variant of uncertain significance has been identified in the KCTD7 gene. The c.456 G>A variant hasnot been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. This variant is not observed in large population cohorts (Lek et al., 2016). Several in silico splice prediction models predict that c.456 G>A strengthens a cryptic splice donor site which may supplant the natural donor site and lead to abnormal gene splicing. However, in the absence of RNA/functional studies, the actual effect of this sequence change in this individual is unknown. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.24

CADD

Benign

DANN

Uncertain

1.0

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.33

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.33

Position offset: -3

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over