3-178828351-A-G

Variant names:

• chr3-178828351-A-G
• rs1417590344
• NM_181361.3:c.401A>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_181361.3(KCNMB2):​c.401A>G​(p.Glu134Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,168 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E134V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNMB2 NM_181361.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.85
• Publications: 0 publications found

Genes affected

KCNMB2 (HGNC:6286): (potassium calcium-activated channel subfamily M regulatory beta subunit 2) MaxiK channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability. MaxiK channels can be formed by 2 subunits: the pore-forming alpha subunit and the modulatory beta subunit. The protein encoded by this gene is an auxiliary beta subunit which decreases the activation time of MaxiK alpha subunit currents. Alternative splicing results in multiple transcript variants of this gene. Additional variants are discussed in the literature, but their full length nature has not been described. [provided by RefSeq, Jul 2013]

ENSG00000275163 (HGNC:):

KCNMB2-AS1 (HGNC:51409): (KCNMB2 antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.816

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_181361.3. 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
	KCNMB2	NM_181361.3	MANE Select	c.401A>G	p.Glu134Gly	missense	Exon 4 of 5	NP_852006.1	Q9Y691
	KCNMB2	NM_001278911.2		c.401A>G	p.Glu134Gly	missense	Exon 4 of 5	NP_001265840.1	Q9Y691
	KCNMB2	NM_005832.5		c.401A>G	p.Glu134Gly	missense	Exon 5 of 6	NP_005823.1	Q9Y691

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNMB2	ENST00000452583.6	TSL:1 MANE Select	c.401A>G	p.Glu134Gly	missense	Exon 4 of 5	ENSP00000397483.1	Q9Y691
	KCNMB2	ENST00000358316.7	TSL:1	c.401A>G	p.Glu134Gly	missense	Exon 3 of 4	ENSP00000351068.3	Q9Y691
	KCNMB2	ENST00000432997.5	TSL:1	c.401A>G	p.Glu134Gly	missense	Exon 4 of 5	ENSP00000407592.1	Q9Y691

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461168 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726876

African (AFR) AF: 0.00 AC: 0 AN: 33456

American (AMR) AF: 0.00 AC: 0 AN: 44650

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39668

South Asian (SAS) AF: 0.00 AC: 0 AN: 86132

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111604

Other (OTH) AF: 0.00 AC: 0 AN: 60376

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.060
CADD	Pathogenic	26
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.18	T
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.022	T
MetaRNN	Pathogenic	0.82	D
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.0	M
PhyloP100		8.8
PrimateAI	Uncertain	0.63	T
PROVEAN	Pathogenic	-4.7	D
REVEL	Uncertain	0.40
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.040	D
Polyphen		0.98	D
Vest4		0.87
MutPred		0.59		Loss of ubiquitination at K137 (P = 0.046)
MVP		0.39
MPC		0.93
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.67
gMVP		0.76
Mutation Taster		=16/84	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1417590344; hg19: chr3-178546139;