rs1556859040

Positions:

• chrX-53234533-G-A

Variant summary

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

The NM_001111125.3(IQSEC2):​c.4153C>T​(p.Pro1385Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000401 in 996,299 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. In-silico tool predicts 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. P1385P) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 20)
  • Exomes 𝑓: 0.0000040 (0 hom. 1 hem.)
• Consequence: IQSEC2 NM_001111125.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.35

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 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=0.20706004).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IQSEC2	NM_001111125.3	c.4153C>T	p.Pro1385Ser	missense_variant	15/15	ENST00000642864.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IQSEC2	ENST00000642864.1	c.4153C>T	p.Pro1385Ser	missense_variant	15/15		NM_001111125.3	P1

Frequencies

GnomAD3 genomes Cov.: 20

GnomAD4 exome AF: 0.00000401 AC: 4 AN: 996299 Hom.: 0 Cov.: 33 AF XY: 0.00000320 AC XY: 1 AN XY: 312259

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000507

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 20

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Intellectual disability, X-linked 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 19, 2017

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with IQSEC2-related disease. While this variant is not present in population databases, the frequency information is unreliable, as metrics indicate poor data quality at this position in the ExAC database. This sequence change replaces proline with serine at codon 1385 of the IQSEC2 protein (p.Pro1385Ser). The proline residue is weakly conserved and there is a moderate physicochemical difference between proline and serine. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 10, 2018

The p.P1385S variant (also known as c.4153C>T), located in coding exon 15 of the IQSEC2 gene, results from a C to T substitution at nucleotide position 4153. The proline at codon 1385 is replaced by serine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.70
CADD	Uncertain	24
DANN	Uncertain	1.0
FATHMM_MKL	Benign	0.60	D
LIST_S2	Benign	0.80	.;T
M_CAP	Uncertain	0.25	D
MetaRNN	Benign	0.21	T;T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	D;N;N
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-0.75	N;.
REVEL	Benign	0.048
Sift	Uncertain	0.0050	D;.
Sift4G	Benign	0.22	T;.
Vest4		0.38
MutPred		0.24		Loss of ubiquitination at K1386 (P = 0.1465);Loss of ubiquitination at K1386 (P = 0.1465);
MVP		0.20
MPC		2.1
ClinPred		0.47	T
GERP RS		2.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.047

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: rs1556859040; hg19: chrX-53263715;