chr3-179242978-C-CT

Position:

• chr3-179242978-C-CT

Variant summary

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

The NM_171830.2(KCNMB3):​c.753_754insA​(p.Val252SerfsTer31) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: not found (cov: 28)
• Consequence: KCNMB3 NM_171830.2 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.485

Genes affected

KCNMB3 (HGNC:6287): (potassium calcium-activated channel subfamily M regulatory beta subunit 3) 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 may partially inactivate or slightly decrease the activation time of MaxiK alpha subunit currents. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 22. [provided by RefSeq, Jul 2009]

ACMG classification

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
KCNMB3	NM_171830.2	c.753_754insA	p.Val252SerfsTer31	frameshift_variant	3/3	ENST00000392685.7	NP_741981.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
KCNMB3	ENST00000392685.7	c.753_754insA	p.Val252SerfsTer31	frameshift_variant	3/3	1	NM_171830.2	ENSP00000376451	P4

Frequencies

GnomAD3 genomes Cov.: 28

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 28

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

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: rs143962239; hg19: chr3-178960766;