Variant X-53291927-G-A details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_001111125.3(IQSEC2):c.708-3C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000012 in 1,164,030 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 3 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000089 ( 0 hom., 0 hem., cov: 22)

Exomes 𝑓: 0.000012 ( 0 hom. 3 hem. )

Consequence

IQSEC2
NM_001111125.3 splice_region, intron

Scores

Splicing: ADA: 0.01065

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:2

Conservation

PhyloP100: 2.42

Variant links:

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]

IQSEC2 links:

IQSEC2 (HGNC:):

IQSEC2 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -6 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.4).

BS2

High Hemizygotes in GnomAdExome4 at 3 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IQSEC2	NM_001111125.3 linkuse as main transcript	c.708-3C>T		splice_region_variant, intron_variant		ENST00000642864.1	NP_001104595.1	Q5JU85-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IQSEC2	ENST00000642864.1 linkuse as main transcript	c.708-3C>T		splice_region_variant, intron_variant			NM_001111125.3	ENSP00000495726.1		Q5JU85-2

Frequencies

GnomAD3 genomes

AF:

0.00000894

AC:

AN:

111852

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

34028

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:

0.0000188

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000175

AC:

AN:

114265

Hom.:

AF XY:

0.00

AC XY:

AN XY:

40689

show subpopulations

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:

0.0000452

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000124

AC:

AN:

1052127

Hom.:

Cov.:

AF XY:

0.00000875

AC XY:

AN XY:

342977

show subpopulations

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:

0.00000978

Gnomad4 OTH exome

AF:

0.000113

GnomAD4 genome

AF:

0.00000894

AC:

AN:

111903

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

34089

show subpopulations

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:

0.0000188

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Tip-toe gait

Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino

Hereditary motor sensory neuropathy (HMSN), also known as Charcot-Marie-Tooth Disease (CMT), is the most commonly inherited peripheral polyneuropathy. It constitutes a group of inherited, progressive, motor and sensory peripheral nerve disorders with properties of demyelination, axonal degeneration, or both. It is classified by clinical characteristics, modes of inheritance, electrophysiologic features, metabolic defects, and specific gene markers. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 04, 2020

The c.708-3C>T intronic alteration results from a C to T substitution 3 nucleotides before coding exon 2 of the IQSEC2 gene. Based on data from the Genome Aggregation Database (gnomAD) database, the IQSEC2 c.708-3C>T alteration was observed in 0.00175% (2/114,265) of total alleles studied, with a frequency of 0.0045% (2/44,211) in the European (non-Finnish) subpopulation. This nucleotide position is conserved in available mammalian species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Intellectual disability, X-linked 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 06, 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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. ClinVar contains an entry for this variant (Variation ID: 567855). This variant has been observed in individual(s) with IQSEC2-related conditions (Invitae). This variant is present in population databases (rs781873807, gnomAD 0.005%). This sequence change falls in intron 1 of the IQSEC2 gene. It does not directly change the encoded amino acid sequence of the IQSEC2 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.40

CADD

Benign

DANN

Benign

0.76

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.011

dbscSNV1_RF

Benign

0.070

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

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