NM_021614.4:c.1779+99C>A

Variant names:

• chr5-114463289-C-A
• rs17136627
• NM_021614.4:c.1779+99C>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_021614.4(KCNN2):​c.1779+99C>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000134 in 743,570 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000013 (0 hom.)
• Consequence: KCNN2 NM_021614.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.219
• Publications: 0 publications found

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]

KCNN2 Gene-Disease associations (from GenCC):

• neurodevelopmental disorder with or without variable movement or behavioral abnormalities

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae)

LOC101927078 (HGNC:):

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.77).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNN2	NM_021614.4	c.1779+99C>A		intron_variant	Intron 4 of 7	ENST00000673685.1	NP_067627.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNN2	ENST00000673685.1	c.1779+99C>A		intron_variant	Intron 4 of 7		NM_021614.4	ENSP00000501239.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000134 AC: 1 AN: 743570 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 381062

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 17374

American (AMR) AF: 0.00 AC: 0 AN: 23332

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 15328

East Asian (EAS) AF: 0.00 AC: 0 AN: 33230

South Asian (SAS) AF: 0.00 AC: 0 AN: 46532

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 45626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3250

European-Non Finnish (NFE) AF: 0.00000191 AC: 1 AN: 524176

Other (OTH) AF: 0.00 AC: 0 AN: 34722

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.77
CADD	Benign	6.4
DANN	Benign	0.71
PhyloP100		-0.22

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

Other links and lift over

dbSNP: rs17136627; hg19: chr5-113798986;