chrX-153787867-C-T

Variant names:

• chrX-153787867-C-T
• NM_004135.4:c.496G>A

Variant summary

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

The NM_004135.4(IDH3G):​c.496G>A​(p.Val166Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 25)
• Consequence: IDH3G NM_004135.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.61

Genes affected

IDH3G (HGNC:5386): (isocitrate dehydrogenase (NAD(+)) 3 non-catalytic subunit gamma) Isocitrate dehydrogenases catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. These enzymes belong to two distinct subclasses, one of which utilizes NAD(+) as the electron acceptor and the other NADP(+). Five isocitrate dehydrogenases have been reported: three NAD(+)-dependent isocitrate dehydrogenases, which localize to the mitochondrial matrix, and two NADP(+)-dependent isocitrate dehydrogenases, one of which is mitochondrial and the other predominantly cytosolic. NAD(+)-dependent isocitrate dehydrogenases catalyze the allosterically regulated rate-limiting step of the tricarboxylic acid cycle. Each isozyme is a heterotetramer that is composed of two alpha subunits, one beta subunit, and one gamma subunit. The protein encoded by this gene is the gamma subunit of one isozyme of NAD(+)-dependent isocitrate dehydrogenase. This gene is a candidate gene for periventricular heterotopia. Several alternatively spliced transcript variants of this gene have been described, but only some of their full length natures have been determined. [provided by RefSeq, Jul 2008]

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=0.25394303).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IDH3G	NM_004135.4	c.496G>A	p.Val166Ile	missense_variant	Exon 7 of 13	ENST00000217901.10	NP_004126.1
IDH3G	NM_174869.3	c.496G>A	p.Val166Ile	missense_variant	Exon 7 of 12		NP_777358.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IDH3G	ENST00000217901.10	c.496G>A	p.Val166Ile	missense_variant	Exon 7 of 13	1	NM_004135.4	ENSP00000217901.5

Frequencies

GnomAD3 genomes Cov.: 25

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 25

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Feb 12, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.496G>A (p.V166I) alteration is located in exon 7 (coding exon 7) of the IDH3G gene. This alteration results from a G to A substitution at nucleotide position 496, causing the valine (V) at amino acid position 166 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.070
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.61
CADD	Benign	16
DANN	Benign	0.87
DEOGEN2	Benign	0.37	.;T;.;T;T;T;T
FATHMM_MKL	Benign	0.56	D
LIST_S2	Uncertain	0.90	D;D;D;.;D;D;D
M_CAP	Benign	0.0099	T
MetaRNN	Benign	0.25	T;T;T;T;T;T;T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	0.57	N;N;.;.;.;.;.
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	0.67	N;N;N;N;.;N;N
REVEL	Benign	0.11
Sift	Benign	1.0	T;T;T;T;.;T;T
Sift4G	Benign	1.0	T;T;T;T;T;T;T
Polyphen		0.025	.;B;.;.;.;.;.
Vest4		0.083
MutPred		0.70		Loss of catalytic residue at V166 (P = 0.2053);Loss of catalytic residue at V166 (P = 0.2053);Loss of catalytic residue at V166 (P = 0.2053);.;.;.;.;
MVP		0.49
MPC		0.88
ClinPred		0.15	T
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.055
gMVP		0.89

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

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-153053322;