chr3-121770422-C-T

Variant names:

• chr3-121770422-C-T
• rs1201232022
• NM_001023570.4:c.1720G>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001023570.4(IQCB1):​c.1720G>A​(p.Asp574Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,614,124 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: IQCB1 NM_001023570.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.24
• Publications: 0 publications found

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):

• ciliopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Senior-Loken syndrome 5

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• Leber congenital amaurosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Senior-Loken syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.0818848).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001023570.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IQCB1	NM_001023570.4	MANE Select	c.1720G>A	p.Asp574Asn	missense	Exon 15 of 15	NP_001018864.2	Q15051-1
	IQCB1	NM_001319107.2		c.1720G>A	p.Asp574Asn	missense	Exon 15 of 15	NP_001306036.1	Q15051-1
	IQCB1	NM_001023571.4		c.1321G>A	p.Asp441Asn	missense	Exon 12 of 12	NP_001018865.2	Q15051-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IQCB1	ENST00000310864.11	TSL:1 MANE Select	c.1720G>A	p.Asp574Asn	missense	Exon 15 of 15	ENSP00000311505.6	Q15051-1
	IQCB1	ENST00000349820.10	TSL:1	c.1321G>A	p.Asp441Asn	missense	Exon 12 of 12	ENSP00000323756.7	Q15051-2
	IQCB1	ENST00000923631.1		c.1792G>A	p.Asp598Asn	missense	Exon 16 of 16	ENSP00000593690.1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152260 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000262

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: 0.00

GnomAD2 exomes AF: 0.00000795 AC: 2 AN: 251454 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461864 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727236

African (AFR) AF: 0.00 AC: 0 AN: 33480

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: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111982

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152260 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74390

African (AFR) AF: 0.00 AC: 0 AN: 41472

American (AMR) AF: 0.000262 AC: 4 AN: 15290

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4834

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10626

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68048

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000189

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Nephronophthisis (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.071
BayesDel_addAF	Benign	-0.38	T
BayesDel_noAF	Benign	-0.61
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.051	T
Eigen	Benign	-0.29
Eigen_PC	Benign	-0.12
FATHMM_MKL	Uncertain	0.76	D
LIST_S2	Benign	0.75	T
M_CAP	Benign	0.0052	T
MetaRNN	Benign	0.082	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.7	L
PhyloP100		2.2
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-1.4	N
REVEL	Benign	0.022
Sift	Benign	0.20	T
Sift4G	Benign	0.40	T
Polyphen		0.0010	B
Vest4		0.076
MutPred		0.24		Loss of phosphorylation at S572 (P = 0.1179)
MVP		0.41
MPC		0.080
ClinPred		0.18	T
GERP RS		3.7
Varity_R		0.047
gMVP		0.13
Mutation Taster		=93/7	polymorphism

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: rs1201232022; hg19: chr3-121489269;