8-139618677-C-T

Variant names:

• chr8-139618677-C-T
• rs121908332
• NM_001282534.2:c.706G>A

Variant summary

Our verdict is Pathogenic. The variant received 24 ACMG points: 24P and 0B. PS1 PS3 PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_001282534.2(KCNK9):​c.706G>A​(p.Gly236Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001251615: Functional studies in mice expressing the mutant showed significantly higher calcium transients as compared to controls (Bando et al. 2014)." and additional evidence is available in ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KCNK9 NM_001282534.2 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:9
• Conservation: PhyloP100: 5.83
• Publications: 27 publications found

Genes affected

KCNK9 (HGNC:6283): (potassium two pore domain channel subfamily K member 9) This gene encodes a protein that contains multiple transmembrane regions and two pore-forming P domains and functions as a pH-dependent potassium channel. Amplification and overexpression of this gene have been observed in several types of human carcinomas. This gene is imprinted in the brain, with preferential expression from the maternal allele. A mutation in this gene was associated with Birk-Barel dysmorphism syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2017]

KCNK9 Gene-Disease associations (from GenCC):

• Birk-Barel syndrome

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

ACMG classification

Our verdict: Pathogenic. The variant received 24 ACMG points.

• PS1: Transcript NM_001282534.2 (KCNK9) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV001251615: Functional studies in mice expressing the mutant showed significantly higher calcium transients as compared to controls (Bando et al. 2014).; SCV000617204: Published functional studies indicate that G236R results in a reduction of current suggestive of a dominant-negative effect (Barel et al., 2008; Veale et al., 2014); PMID: 18678320, 24342771, 27378938, 27151206, 30577886, 23236211
• PM1: In a helix (size 29) in uniprot entity KCNK9_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_001282534.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.96
• PP5: Variant 8-139618677-C-T is Pathogenic according to our data. Variant chr8-139618677-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 4741.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001282534.2. 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
	KCNK9	NM_001282534.2	MANE Select	c.706G>A	p.Gly236Arg	missense	Exon 2 of 2	NP_001269463.1	Q9NPC2
	KCNK9	NR_104210.2		n.837G>A		non_coding_transcript_exon	Exon 2 of 4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KCNK9	ENST00000520439.3	TSL:1 MANE Select	c.706G>A	p.Gly236Arg	missense	Exon 2 of 2	ENSP00000430676.1	Q9NPC2
	KCNK9	ENST00000303015.2	TSL:1	c.706G>A	p.Gly236Arg	missense	Exon 2 of 3	ENSP00000302166.1	Q9NPC2
	KCNK9	ENST00000648164.1		c.706G>A	p.Gly236Arg	missense	Exon 2 of 2	ENSP00000498198.1	Q9NPC2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
6	-	-	Birk-Barel syndrome (6)
3	-	-	not provided (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Uncertain	0.090
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.73	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Benign	0.035	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Benign	-0.41	T
MutationAssessor	Pathogenic	3.1	M
PhyloP100		5.8
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-5.0	D
REVEL	Uncertain	0.55
Sift	Uncertain	0.022	D
Sift4G	Uncertain	0.025	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.92		Gain of methylation at G236 (P = 0.0193)
MVP		0.81
MPC		2.5
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.88
gMVP		0.99
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs121908332; hg19: chr8-140630920; COSMIC: COSV57283374; COSMIC: COSV57283374;