chr8-139618483-G-A

Variant names:

• chr8-139618483-G-A
• rs1455162694
• NM_001282534.2:c.900C>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_001282534.2(KCNK9):​c.900C>T​(p.Thr300Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,574 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. Synonymous variant affecting the same amino acid position (i.e. T300T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KCNK9 NM_001282534.2 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.78
• 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, G2P, Illumina, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.47).
• BP7: Synonymous conserved (PhyloP=1.78 with no splicing effect.

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.900C>T	p.Thr300Thr	synonymous	Exon 2 of 2	NP_001269463.1	Q9NPC2
	KCNK9	NR_104210.2		n.1031C>T		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.900C>T	p.Thr300Thr	synonymous	Exon 2 of 2	ENSP00000430676.1	Q9NPC2
	KCNK9	ENST00000303015.2	TSL:1	c.900C>T	p.Thr300Thr	synonymous	Exon 2 of 3	ENSP00000302166.1	Q9NPC2
	KCNK9	ENST00000648164.1		c.900C>T	p.Thr300Thr	synonymous	Exon 2 of 2	ENSP00000498198.1	Q9NPC2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461574 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 727102

⚠️ 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: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53104

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112008

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

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.47
CADD	Benign	5.4
DANN	Benign	0.83
PhyloP100		1.8

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1455162694; hg19: chr8-140630726;