3-121770391-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001023570.4(IQCB1):c.1751G>A(p.Ser584Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,614,030 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. S584S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000059 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: IQCB1 NM_001023570.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.581

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08006281).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IQCB1	NM_001023570.4	c.1751G>A	p.Ser584Asn	missense_variant	15/15	ENST00000310864.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IQCB1	ENST00000310864.11	c.1751G>A	p.Ser584Asn	missense_variant	15/15	1	NM_001023570.4	P1
IQCB1	ENST00000349820.10	c.1352G>A	p.Ser451Asn	missense_variant	12/12	1
IQCB1	ENST00000393650.7	c.*729G>A		3_prime_UTR_variant, NMD_transcript_variant	14/14	5

Frequencies

GnomAD3 genomes AF: 0.0000591 AC: 9 AN: 152208 Hom.: 0 Cov.: 32

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: 0.000132

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000795 AC: 2 AN: 251436 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135898

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000150 AC: 22 AN: 1461822 Hom.: 0 Cov.: 31 AF XY: 0.0000248 AC XY: 18 AN XY: 727216

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000562

Gnomad4 NFE exome AF: 0.0000162

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000591 AC: 9 AN: 152208 Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5 AN XY: 74368

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000132

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000274 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nephronophthisis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 08, 2023

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt IQCB1 protein function. ClinVar contains an entry for this variant (Variation ID: 1429502). This variant has not been reported in the literature in individuals affected with IQCB1-related conditions. This variant is present in population databases (rs762365184, gnomAD 0.009%). This sequence change replaces serine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 584 of the IQCB1 protein (p.Ser584Asn). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.54	T
BayesDel_noAF	Benign	-0.65
Cadd	Benign	16
Dann	Benign	0.97
DEOGEN2	Benign	0.023	T;.
Eigen	Benign	-0.61
Eigen_PC	Benign	-0.49
FATHMM_MKL	Benign	0.33	N
LIST_S2	Benign	0.56	T;T
M_CAP	Benign	0.0060	T
MetaRNN	Benign	0.080	T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.6	L;.
MutationTaster	Benign	0.98	N;N
PrimateAI	Benign	0.40	T
PROVEAN	Benign	-0.29	N;N
REVEL	Benign	0.027
Sift	Benign	0.27	T;T
Sift4G	Benign	0.99	T;T
Polyphen		0.0030	B;B
Vest4		0.021
MutPred		0.46		Loss of phosphorylation at S584 (P = 0.0277);.;
MVP		0.22
MPC		0.076
ClinPred		0.043	T
GERP RS		2.6
Varity_R		0.022
gMVP		0.060

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

Other links and lift over

dbSNP: rs762365184; hg19: chr3-121489238; COSMIC: COSV105878280;