5-114362776-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_021614.4(KCNN2):c.637A>G(p.Met213Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000697 in 1,433,802 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 (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: KCNN2 NM_021614.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.75

Genes affected

KCNN2 (HGNC:6291): (potassium calcium-activated channel subfamily N member 2) 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. The protein encoded by this gene is activated before membrane hyperpolarization and is thought to regulate neuronal excitability by contributing to the slow component of synaptic AHP. This gene is a member of the KCNN family of potassium channel genes. The encoded protein is an integral membrane protein that forms a voltage-independent calcium-activated channel with three other calmodulin-binding subunits. Alternate splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2013]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNN2	NM_021614.4	c.637A>G	p.Met213Val	missense_variant	1/8	ENST00000673685.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNN2	ENST00000673685.1	c.637A>G	p.Met213Val	missense_variant	1/8		NM_021614.4	P2
KCNN2	ENST00000512097.10	c.835A>G	p.Met279Val	missense_variant	6/13	5		A2
KCNN2	ENST00000631899.2	c.40A>G	p.Met14Val	missense_variant	1/9	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.97e-7 AC: 1 AN: 1433802 Hom.: 0 Cov.: 30 AF XY: 0.00000140 AC XY: 1 AN XY: 712016

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: 9.06e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 21, 2022

Not observed at significant frequency in large population cohorts (gnomAD); Initiation codon variant with an unclear effect on protein function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
Cadd	Uncertain	25
Dann	Uncertain	1.0
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	0.98	D;D
REVEL	Pathogenic	0.83
Polyphen		0.99	.;D
Vest4		0.92
MutPred		0.99		.;Loss of phosphorylation at S2 (P = 0.1454);
MVP		0.98
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.85
gMVP		0.67

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

LitVar

Other links and lift over

dbSNP: rs1296103242; hg19: chr5-113698473;