Genetic Variant KCNN3:p.Met638Ile (chr1-154708258-C-G) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BS2

The NM_002249.6(KCNN3):c.1914G>C(p.Met638Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,613,432 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

KCNN3
NM_002249.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.55

Variant links:

Genes affected

KCNN3 (HGNC:6292): (potassium calcium-activated channel subfamily N member 3) Action potentials in vertebrate neurons are followed by an afterhyperpolarization (AHP) that may persist for several seconds and may have profound consequences for the firing pattern of the neuron. Each component of the AHP is kinetically distinct and is mediated by different calcium-activated potassium channels. This gene belongs to the KCNN family of potassium channels. It encodes an integral membrane protein that forms a voltage-independent calcium-activated channel, which is thought to regulate neuronal excitability by contributing to the slow component of synaptic AHP. This gene contains two CAG repeat regions in the coding sequence. It was thought that expansion of one or both of these repeats could lead to an increased susceptibility to schizophrenia or bipolar disorder, but studies indicate that this is probably not the case. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Feb 2011]

KCNN3 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BS2

High AC in GnomAdExome4 at 16 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNN3	NM_002249.6 link	c.1914G>C	p.Met638Ile	missense_variant	Exon 8 of 8	ENST00000271915.9	NP_002240.3	Q9UGI6-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNN3	ENST00000271915.9 link	c.1914G>C	p.Met638Ile	missense_variant	Exon 8 of 8	1	NM_002249.6	ENSP00000271915.3		Q9UGI6-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000109

AC:

AN:

1461302

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

726966

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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:

0.0000144

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152130

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74330

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

May 16, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1914G>C (p.M638I) alteration is located in exon 8 (coding exon 8) of the KCNN3 gene. This alteration results from a G to C substitution at nucleotide position 1914, causing the methionine (M) at amino acid position 638 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.94

BayesDel_addAF

Pathogenic

0.52

BayesDel_noAF

Pathogenic

0.50

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Benign

0.28

.;T;.;.

Eigen

Uncertain

0.40

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.88

D;D;D;D

M_CAP

Uncertain

0.17

MetaRNN

Uncertain

0.65

D;D;D;D

MetaSVM

Pathogenic

1.1

PrimateAI

Pathogenic

0.84

PROVEAN

Benign

-1.9

N;.;N;N

REVEL

Pathogenic

0.72

Sift

Benign

0.047

D;.;T;T

Sift4G

Benign

0.10

T;T;T;T

Polyphen

0.0080

.;.;B;.

Vest4

0.71

MVP

0.93

MPC

1.4

ClinPred

0.72

GERP RS

5.1

Varity_R

0.43

gMVP

0.86

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

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