11-128838261-C-A

Variant names:

• chr11-128838261-C-A
• rs139805663
• NM_153766.3:c.*864G>T

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BS1_Supporting

The NM_153766.3(KCNJ1):​c.*864G>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00244 in 152,250 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0024 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: KCNJ1 NM_153766.3 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.119
• Publications: 0 publications found

Genes affected

KCNJ1 (HGNC:6255): (potassium inwardly rectifying channel subfamily J member 1) Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. It is activated by internal ATP and probably plays an important role in potassium homeostasis. The encoded protein has a greater tendency to allow potassium to flow into a cell rather than out of a cell. Mutations in this gene have been associated with antenatal Bartter syndrome, which is characterized by salt wasting, hypokalemic alkalosis, hypercalciuria, and low blood pressure. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

KCNJ1 Gene-Disease associations (from GenCC):

• Bartter disease type 2

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• antenatal Bartter syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.89).
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00244 (371/152250) while in subpopulation AFR AF = 0.00852 (354/41530). AF 95% confidence interval is 0.00779. There are 0 homozygotes in GnomAd4. There are 184 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KCNJ1	NM_153766.3	c.*864G>T		3_prime_UTR_variant	Exon 3 of 3	ENST00000392666.6	NP_722450.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KCNJ1	ENST00000392666.6	c.*864G>T		3_prime_UTR_variant	Exon 3 of 3	1	NM_153766.3	ENSP00000376434.1
KCNJ1	ENST00000324036.7	c.*864G>T		3_prime_UTR_variant	Exon 4 of 4	1		ENSP00000316233.3
KCNJ1	ENST00000392665.6	c.*864G>T		3_prime_UTR_variant	Exon 2 of 2	1		ENSP00000376433.2
KCNJ1	ENST00000440599.6	c.*864G>T		3_prime_UTR_variant	Exon 3 of 3	1		ENSP00000406320.2

Frequencies

GnomAD3 genomes AF: 0.00244 AC: 371 AN: 152132 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00855

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000720

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00192

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 452 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 272

African (AFR) AC: 0 AN: 0

American (AMR) AC: 0 AN: 0

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AC: 0 AN: 0

South Asian (SAS) AC: 0 AN: 0

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 424

Middle Eastern (MID) AC: 0 AN: 0

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 22

Other (OTH) AF: 0.00 AC: 0 AN: 6

GnomAD4 genome AF: 0.00244 AC: 371 AN: 152250 Hom.: 0 Cov.: 32 AF XY: 0.00247 AC XY: 184 AN XY: 74462

African (AFR) AF: 0.00852 AC: 354 AN: 41530

American (AMR) AF: 0.000719 AC: 11 AN: 15296

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5172

South Asian (SAS) AF: 0.00 AC: 0 AN: 4822

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68030

Other (OTH) AF: 0.00190 AC: 4 AN: 2110

Alfa AF: 0.00132 Hom.: 0

Bravo AF: 0.00270

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bartter disease type 2 Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	1.7
DANN	Benign	0.51
PhyloP100		0.12

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: rs139805663; hg19: chr11-128708156;