NM_001128178.3:c.555dupA

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_001128178.3(NPHP1):c.555dupA(p.Pro186ThrfsTer2) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000067 in 1,610,742 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. K185K) has been classified as Uncertain significance. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000069 ( 0 hom. )

Consequence

NPHP1
NM_001128178.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:12

Conservation

PhyloP100: -0.0950

Publications

4 publications found

Variant links:

Genes affected

NPHP1 (HGNC:7905): (nephrocystin 1) This gene encodes a protein with src homology domain 3 (SH3) patterns. This protein interacts with Crk-associated substrate, and it appears to function in the control of cell division, as well as in cell-cell and cell-matrix adhesion signaling, likely as part of a multifunctional complex localized in actin- and microtubule-based structures. Mutations in this gene cause familial juvenile nephronophthisis type 1, a kidney disorder involving both tubules and glomeruli. Defects in this gene are also associated with Senior-Loken syndrome type 1, also referred to as juvenile nephronophthisis with Leber amaurosis, which is characterized by kidney and eye disease, and with Joubert syndrome type 4, which is characterized by cerebellar ataxia, oculomotor apraxia, psychomotor delay and neonatal breathing abnormalities, sometimes including retinal dystrophy and renal disease. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

NPHP1 Gene-Disease associations (from GenCC):

Joubert syndrome with renal defect
Inheritance: AR Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, G2P
nephronophthisis 1
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, ClinGen, Labcorp Genetics (formerly Invitae)
Bardet-Biedl syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
Senior-Loken syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

NPHP1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-110168520-G-GT is Pathogenic according to our data. Variant chr2-110168520-G-GT is described in ClinVar as Pathogenic. ClinVar VariationId is 283524.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NPHP1	NM_001128178.3 link	c.555dupA	p.Pro186ThrfsTer2	frameshift_variant	Exon 6 of 20	ENST00000445609.7	NP_001121650.1	O15259-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NPHP1	ENST00000445609.7 link	c.555dupA	p.Pro186ThrfsTer2	frameshift_variant	Exon 6 of 20	1	NM_001128178.3	ENSP00000389879.3		O15259-2

Frequencies

GnomAD3 genomes

AF:

0.0000462

AC:

AN:

151366

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000486

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000737

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000399

AC:

AN:

250786

AF XY:

0.00000738

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000692

AC:

101

AN:

1459376

Hom.:

Cov.:

AF XY:

0.0000661

AC XY:

AN XY:

726154

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000598

AC:

AN:

33422

American (AMR)

AF:

0.00

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26104

East Asian (EAS)

AF:

0.00

AC:

AN:

39624

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86162

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53374

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000811

AC:

AN:

1109934

Other (OTH)

AF:

0.0000995

AC:

AN:

60286

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000000000877076), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.395

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000462

AC:

AN:

151366

Hom.:

Cov.:

AF XY:

0.0000812

AC XY:

AN XY:

73864

show subpopulations

African (AFR)

AF:

0.0000486

AC:

AN:

41134

American (AMR)

AF:

0.00

AC:

AN:

15194

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3458

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4794

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10422

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000737

AC:

AN:

67878

Other (OTH)

AF:

0.00

AC:

AN:

2080

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.411

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:12

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Nephronophthisis 1

Pathogenic:4

Neuberg Centre For Genomic Medicine, NCGM

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The frameshift duplication p.P186Tfs*2 in NPHP1 (NM_001128178.3) has been previously reported in affected patients(Caridi G et al). The variant has been submitted to ClinVar as Pathogenic. The p.P186Tfs*2 variant is novel (not in any individuals) in 1000 Genomes. This variant is predicted to cause loss of normal protein function through protein truncation caused a frameshift mutation. The frame shifted sequence continues 2 residues until a stop codon is reached. For these reasons, this variant has been classified as Pathogenic. -

Jun 30, 2016

Genetic Services Laboratory, University of Chicago

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 14, 2019

Yale Center for Mendelian Genomics, Yale University

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Jan 18, 2022

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

- -

Nephronophthisis

Pathogenic:3

Mar 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Pro186Thrfs*2) in the NPHP1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in NPHP1 are known to be pathogenic (PMID: 23559409). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This premature translational stop signal has been observed in individual(s) with nephronophthisis or a related ciliopathy (PMID: 16762963, 18076122, 23559409). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as c.548_555dupA (p.Glu183fs). ClinVar contains an entry for this variant (Variation ID: 283524). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Aug 29, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Pro186ThrfsX2 variant in NPHP1 has been reported in 1 individual with neph ronopthisis in the compound heterozygous state with a full gene deletion of NPHP 1 (Caridi 2006), which is the most common pathogenic change involving this gene. It was absent from large population studies. This variant is predicted to cause a frameshift, which alters the protein?s amino acid sequence beginning at posit ion 186 and leads to a premature termination codon 2 amino acids downstream. Thi s alteration is then predicted to lead to a truncated or absent protein. In summ ary, this variant meets criteria to be classified as pathogenic for autosomal re cessive nephronopthisis based on absence from controls, predicted impact on prot ein, and a case observation. ACMG/AMP criteria applied: PVS1, PM2, PM3. -

Oct 10, 2017

Sydney Genome Diagnostics, Children's Hospital Westmead

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This frameshifting variant, c.555dup, is predicted to create a premature stop codon 2 positions downstream p.(Pro186Thrfs*2), and may result in a null allele due to nonsense-mediated mRNA decay. This variant has not been reported in any population databases (i.e. ExAC, ESP or dbSNP). It has been previously reported in a patient with nephronophthisis, who was compound heterozygous with a deletion of the entire NPHP1 gene (Otto et al 2008 Hum Mutat 29:418-426). Other truncating variants downstream of this amino acid have also been reported in patients with nephronophthisis in the same paper. This variant is considered to be pathogenic according to the ACMG guidelines. -

not provided

Pathogenic:2

Oct 05, 2015

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 29, 2024

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Observed in homozygous state or with an additional NPHP1 variant in patients with nephronophthisis in the literature (PMID: 16762963, 23559409, 30773290); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 16762963, 23559409, 30773290, 31589614, 36990420, 31822006, 18076122) -

Inborn genetic diseases

Pathogenic:1

Jan 28, 2025

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.555dupA (p.P186Tfs*2) alteration, located in exon 6 (coding exon 6) of the NPHP1 gene, consists of a duplication of A at position 555, causing a translational frameshift with a predicted alternate stop codon after 2 amino acids. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on data from gnomAD, the AA allele has an overall frequency of 0.001% (2/282044) total alleles studied. The highest observed frequency was 0.004% (1/24920) of African alleles. This alteration has been reported in the homozygous and compound heterozygous states in multiple patients with NPHP1-related kidney disease including tubulointerstitial kidney disease, nephronophthisis, bilateral small kidneys, and end stage renal disease (Otto, 2008; Halbritter, 2013; Connaughton, 2019; Murray, 2020). Based on the available evidence, this alteration is classified as pathogenic. -

Joubert syndrome with renal defect

Pathogenic:1

Mar 02, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Joubert syndrome with renal defect;C1855681:Nephronophthisis 1;C4551559:Senior-Loken syndrome 1

Pathogenic:1

Mar 04, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

-0.095

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over