rs1556880174

Variant names:

• chrX-53320732-C-G
• rs1556880174
• NM_001111125.3:c.392G>C

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_001111125.3(IQSEC2):​c.392G>C​(p.Arg131Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000664 in 1,053,503 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 2 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000066 (0 hom. 2 hem.)
• Consequence: IQSEC2 NM_001111125.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0310

Genes affected

IQSEC2 (HGNC:29059): (IQ motif and Sec7 domain ArfGEF 2) This gene encodes a guanine nucleotide exchange factor for the ARF family of small GTP-binding proteins. The encoded protein is a component of the postsynaptic density at excitatory synapses, and may play a critical role in cytoskeletal and synaptic organization through the activation of selected ARF substrates including ARF1 and ARF6. Mutations in this gene have been implicated in nonsyndromic X-linked cognitive disability. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.14843887).
• BS2: High Hemizygotes in GnomAdExome4 at 2 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IQSEC2	NM_001111125.3	c.392G>C	p.Arg131Pro	missense_variant	Exon 1 of 15	ENST00000642864.1	NP_001104595.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IQSEC2	ENST00000642864.1	c.392G>C	p.Arg131Pro	missense_variant	Exon 1 of 15		NM_001111125.3	ENSP00000495726.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 0.00000664 AC: 7 AN: 1053503 Hom.: 0 Cov.: 32 AF XY: 0.00000580 AC XY: 2 AN XY: 344619

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000369

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000732

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, X-linked 1 Uncertain:1

Dec 17, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 131 of the IQSEC2 protein (p.Arg131Pro). 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 variant has not been reported in the literature in individuals affected with IQSEC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 538605). 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 IQSEC2 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.58
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.012	.;T;T
FATHMM_MKL	Benign	0.67	D
LIST_S2	Benign	0.82	T;.;T
M_CAP	Uncertain	0.20	D
MetaRNN	Benign	0.15	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.69	.;N;N
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	0.21	.;N;.
REVEL	Benign	0.086
Sift	Pathogenic	0.0	.;D;.
Sift4G	Benign	0.34	.;T;.
Vest4		0.31
MutPred		0.28		Loss of MoRF binding (P = 0.0603);Loss of MoRF binding (P = 0.0603);Loss of MoRF binding (P = 0.0603);
MVP		0.30
MPC		1.8
ClinPred		0.38	T
GERP RS		3.0
Varity_R		0.35
gMVP		0.67

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs1556880174; hg19: chrX-53349930;