chr8-139618406-T-C

Variant names:

• chr8-139618406-T-C
• rs1004131782
• NM_001282534.2:c.977A>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001282534.2(KCNK9):​c.977A>G​(p.Tyr326Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. Y326Y) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KCNK9 NM_001282534.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.68
• Publications: 0 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, Illumina, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.24105105).

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.977A>G	p.Tyr326Cys	missense	Exon 2 of 2	NP_001269463.1	Q9NPC2
	KCNK9	NR_104210.2		n.1108A>G		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.977A>G	p.Tyr326Cys	missense	Exon 2 of 2	ENSP00000430676.1	Q9NPC2
	KCNK9	ENST00000303015.2	TSL:1	c.977A>G	p.Tyr326Cys	missense	Exon 2 of 3	ENSP00000302166.1	Q9NPC2
	KCNK9	ENST00000648164.1		c.977A>G	p.Tyr326Cys	missense	Exon 2 of 2	ENSP00000498198.1	Q9NPC2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461888 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 727242

⚠️ 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: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203476), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.073
BayesDel_addAF	Benign	-0.22	T
BayesDel_noAF	Benign	-0.56
CADD	Benign	16
DANN	Benign	0.93
DEOGEN2	Uncertain	0.51	D
Eigen	Benign	-0.37
Eigen_PC	Benign	-0.46
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.86	D
M_CAP	Benign	0.0053	T
MetaRNN	Benign	0.24	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.6	L
PhyloP100		1.7
PrimateAI	Benign	0.45	T
PROVEAN	Uncertain	-2.7	D
REVEL	Benign	0.13
Sift	Benign	0.070	T
Sift4G	Benign	0.066	T
Polyphen		0.95	P
Vest4		0.58
MutPred		0.29		Loss of loop (P = 0.0986)
MVP		0.54
MPC		2.2
ClinPred		0.61	D
GERP RS		2.2
Varity_R		0.11
gMVP		0.69
Mutation Taster		=85/15	polymorphism

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: rs1004131782; hg19: chr8-140630649;