rs138120505

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM2PP3BP4_Strong

The NM_153766.3(KCNJ1):c.505C>T(p.Arg169Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000141 in 1,613,726 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R169H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00074 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000078 ( 0 hom. )

Consequence

KCNJ1
NM_153766.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:3

Conservation

PhyloP100: 1.64

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Multiple lines of computational evidence support a deleterious effect 6: AlphaMissense, BayesDel_noAF, M_CAP, MutationAssessor, PROVEAN, REVEL [when FATHMM_MKL, MetaRNN, MutationTaster, phyloP100way_vertebrate was below the threshold]

BP4

Computational evidence support a benign effect (MetaRNN=0.057123423).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KCNJ1	NM_153766.3 linkuse as main transcript	c.505C>T	p.Arg169Cys	missense_variant	3/3	ENST00000392666.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KCNJ1	ENST00000392666.6 linkuse as main transcript	c.505C>T	p.Arg169Cys	missense_variant	3/3	1	NM_153766.3	P1	P48048-2

Frequencies

GnomAD3 genomes

AF:

0.000710

AC:

108

AN:

152134

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00239

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000458

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:

0.00

Gnomad OTH

AF:

0.000958

GnomAD3 exomes

AF:

0.000244

AC:

AN:

249916

Hom.:

AF XY:

0.000192

AC XY:

AN XY:

135386

show subpopulations

Gnomad AFR exome

AF:

0.00295

Gnomad AMR exome

AF:

0.000174

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.0000925

Gnomad NFE exome

AF:

0.0000177

Gnomad OTH exome

AF:

0.000327

GnomAD4 exome

AF:

0.0000780

AC:

114

AN:

1461474

Hom.:

Cov.:

AF XY:

0.0000729

AC XY:

AN XY:

727012

show subpopulations

Gnomad4 AFR exome

AF:

0.00200

Gnomad4 AMR exome

AF:

0.000268

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000756

Gnomad4 SAS exome

AF:

0.0000812

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.0000108

Gnomad4 OTH exome

AF:

0.000199

GnomAD4 genome

AF:

0.000742

AC:

113

AN:

152252

Hom.:

Cov.:

AF XY:

0.000819

AC XY:

AN XY:

74444

show subpopulations

Gnomad4 AFR

AF:

0.00250

Gnomad4 AMR

AF:

0.000458

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000948

Alfa

AF:

0.000160

Hom.:

Bravo

AF:

0.000812

ESP6500AA

AF:

0.00432

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000280

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Dec 14, 2016	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Mar 28, 2022	Variant summary: KCNJ1 c.562C>T (p.Arg188Cys) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00024 in 249916 control chromosomes, predominantly at a frequency of 0.003 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 2.7 fold of the estimated maximal expected allele frequency for a pathogenic variant in KCNJ1 causing Bartter Syndrome, Type 2 phenotype (0.0011), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. c.562C>T has been reported in the literature as a heterozygous non-informative (second allele not specified) genotype in at-least one individual of Congolese ethnic origin (African subcontinent) reportedly affected with neonatal Bartter Syndrome, Type 2 (example, Brochard_2009). These report(s) do not provide unequivocal conclusions about association of the variant with Bartter Syndrome, Type 2. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as likely benign and one laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as likely benign. -

Bartter disease type 2

Uncertain:1

Uncertain significance, criteria provided, single submitter

reference population

Soonchunhyang University Bucheon Hospital, Soonchunhyang University Medical Center

Mar 18, 2016

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 07, 2022

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 188 of the KCNJ1 protein (p.Arg188Cys). This variant is present in population databases (rs138120505, gnomAD 0.3%). This missense change has been observed in individual(s) with clinical features of Bartter syndrome (PMID: 19096086). ClinVar contains an entry for this variant (Variation ID: 225398). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The cysteine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Inborn genetic diseases

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 25, 2022

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.93

BayesDel_addAF

Uncertain

0.074

BayesDel_noAF

Pathogenic

0.33

Cadd

Uncertain

Dann

Uncertain

1.0

Eigen

Uncertain

0.38

Eigen_PC

Uncertain

0.37

FATHMM_MKL

Uncertain

0.91

M_CAP

Pathogenic

0.34

MetaRNN

Benign

0.057

T;T;T;T;T

MetaSVM

Pathogenic

0.85

MutationTaster

Benign

1.0

D;D;D;D;D

PrimateAI

Uncertain

0.70

PROVEAN

Pathogenic

-7.6

D;D;D;D;D

REVEL

Pathogenic

0.79

Sift

Uncertain

0.0050

D;D;D;D;D

Sift4G

Uncertain

0.011

D;D;D;D;D

Polyphen

0.73

.;.;.;.;P

Vest4

0.67

MVP

0.95

MPC

0.049

ClinPred

0.19

GERP RS

3.9

Varity_R

0.75

gMVP

0.95

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over