rs373909351

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_001023570.4(IQCB1):​c.1465C>T​(p.Arg489*) variant causes a stop gained change. The variant allele was found at a frequency of 0.0000446 in 1,614,054 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R489R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000048 ( 0 hom. )

Consequence

IQCB1
NM_001023570.4 stop_gained

Scores

2
4
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:11

Conservation

PhyloP100: 3.66

Publications

15 publications found
Variant links:
Genes affected
IQCB1 (HGNC:28949): (IQ motif containing B1) This gene encodes a nephrocystin protein that interacts with calmodulin and the retinitis pigmentosa GTPase regulator protein. The encoded protein has a central coiled-coil region and two calmodulin-binding IQ domains. It is localized to the primary cilia of renal epithelial cells and connecting cilia of photoreceptor cells. The protein is thought to play a role in ciliary function. Defects in this gene result in Senior-Loken syndrome type 5. Alternative splicing results in multiple transcript variants. A pseudogene of this gene is found on chromosome 6. [provided by RefSeq, Jan 2016]
IQCB1 Gene-Disease associations (from GenCC):
  • Senior-Loken syndrome 5
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
  • Leber congenital amaurosis
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Senior-Loken syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PP5
Variant 3-121772659-G-A is Pathogenic according to our data. Variant chr3-121772659-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 30778.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
IQCB1NM_001023570.4 linkc.1465C>T p.Arg489* stop_gained Exon 14 of 15 ENST00000310864.11 NP_001018864.2 Q15051-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
IQCB1ENST00000310864.11 linkc.1465C>T p.Arg489* stop_gained Exon 14 of 15 1 NM_001023570.4 ENSP00000311505.6 Q15051-1
IQCB1ENST00000349820.10 linkc.1066C>T p.Arg356* stop_gained Exon 11 of 12 1 ENSP00000323756.7 Q15051-2
IQCB1ENST00000393650.7 linkn.*443C>T non_coding_transcript_exon_variant Exon 13 of 14 5 ENSP00000377261.3 Q15051-3
IQCB1ENST00000393650.7 linkn.*443C>T 3_prime_UTR_variant Exon 13 of 14 5 ENSP00000377261.3 Q15051-3

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152208
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000278
AC:
7
AN:
251408
AF XY:
0.0000294
show subpopulations
Gnomad AFR exome
AF:
0.0000615
Gnomad AMR exome
AF:
0.0000578
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.0000462
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000479
AC:
70
AN:
1461846
Hom.:
0
Cov.:
32
AF XY:
0.0000426
AC XY:
31
AN XY:
727226
show subpopulations
African (AFR)
AF:
0.0000896
AC:
3
AN:
33478
American (AMR)
AF:
0.0000224
AC:
1
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:
0.0000580
AC:
5
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000522
AC:
58
AN:
1111974
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
4
9
13
18
22
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<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:
0.0000131
AC:
2
AN:
152208
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74352
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41446
American (AMR)
AF:
0.00
AC:
0
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10608
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68048
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000229
Hom.:
0
Bravo
AF:
0.0000302
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.0000247
AC:
3
EpiCase
AF:
0.0000545
EpiControl
AF:
0.00

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:11
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Senior-Loken syndrome 5 Pathogenic:8
Feb 08, 2024
Baylor Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Mar 04, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 01, 2011
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

May 28, 2019
Mendelics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

-
Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

A known stop-gain variant, c.1465C>T in exon 14 of IQCB1 was identified in a homozygous state in the proband (Halbritter et al, 2013). Sanger validation and segregation showed that the variant was present in a homozygous state in the proband and heterozygous state in her parents. The variant is present in 72 individuals in a heterozygous state and absent in a homozygous state in gnomAD (v4.1.0). The variant is absent in homozygous and/or heterozygous state our in-house database of 3274 exomes. This variant is predicted to introduce a premature termination codon which will either cause the transcript to undergo nonsense-mediated mRNA decay or lead to formation of a truncated protein product. -

Mar 15, 2022
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

- -

Jan 01, 2024
Daryl Scott Lab, Baylor College of Medicine
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

PVS1, PS4, PM3 -

May 23, 2017
Undiagnosed Diseases Network, NIH
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The maternally-inherited c.1465C>T is a nonsense variant, which is predicted to result in loss of function in the IQCB1 gene where loss of function is a known mechanism of Senior-Loken syndrome 5, MIM 609254. The c.1465C>T variant was observed to be in trans with a c.1518_1519delCA pathogenic variant based on segregation analysis in the family. Both variants are also also present in the patient's similarly affected sister. -

Retinal dystrophy Pathogenic:2
Nov 24, 2017
Blueprint Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 01, 2017
Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Nephronophthisis Pathogenic:1
Sep 18, 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.Arg489*) in the IQCB1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in IQCB1 are known to be pathogenic (PMID: 15723066, 21901789, 23559409, 28041643). This variant is present in population databases (rs373909351, gnomAD 0.007%). This premature translational stop signal has been observed in individual(s) with autosomal recessive Leber congenital amaurosis and early onset retinitis pigmentosa (PMID: 18076122, 20881296, 21220633, 23847139, 24066033, 29053603). This variant is also known as c.1381C>T, Arg461*. ClinVar contains an entry for this variant (Variation ID: 30778). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.49
D
BayesDel_noAF
Pathogenic
0.51
CADD
Pathogenic
43
DANN
Uncertain
1.0
Eigen
Uncertain
0.51
Eigen_PC
Uncertain
0.32
FATHMM_MKL
Uncertain
0.88
D
PhyloP100
3.7
Vest4
0.23
GERP RS
4.1
Mutation Taster
=1/199
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.020
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs373909351; hg19: chr3-121491506; API