chr15-78149423-T-C

Position:

• chr15-78149423-T-C

Variant summary

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

The NM_005530.3(IDH3A):​c.20T>C​(p.Ile7Thr) 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. 12/21 in silico tools predict 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. I7I) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: IDH3A NM_005530.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.12

Genes affected

IDH3A (HGNC:5384): (isocitrate dehydrogenase (NAD(+)) 3 catalytic subunit alpha) 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 alpha subunit of one isozyme of NAD(+)-dependent isocitrate dehydrogenase. [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=0.17025849).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDH3A	NM_005530.3	c.20T>C	p.Ile7Thr	missense_variant	1/11	ENST00000299518.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDH3A	ENST00000299518.7	c.20T>C	p.Ile7Thr	missense_variant	1/11	1	NM_005530.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 28, 2022

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. This variant has not been reported in the literature in individuals affected with IDH3A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 7 of the IDH3A protein (p.Ile7Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
BayesDel_addAF	Uncertain	0.023	T
BayesDel_noAF	Benign	-0.21
CADD	Benign	21
DANN	Benign	0.96
DEOGEN2	Benign	0.33	T;T;T;T;T
Eigen	Benign	-0.44
Eigen_PC	Benign	-0.23
FATHMM_MKL	Benign	0.59	D
LIST_S2	Benign	0.67	T;T;T;T;T
M_CAP	Pathogenic	0.54	D
MetaRNN	Benign	0.17	T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.0	N;.;.;.;.
MutationTaster	Benign	1.0	D;N;N;N
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-0.050	N;N;N;N;.
REVEL	Benign	0.29
Sift	Benign	0.45	T;T;T;D;.
Sift4G	Benign	0.54	T;T;T;D;D
Polyphen		0.0	B;.;.;.;.
Vest4		0.32
MutPred		0.50		Gain of disorder (P = 0.0216);Gain of disorder (P = 0.0216);Gain of disorder (P = 0.0216);Gain of disorder (P = 0.0216);Gain of disorder (P = 0.0216);
MVP		0.60
MPC		1.1
ClinPred		0.55	D
GERP RS		4.2
Varity_R		0.069
gMVP		0.60

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: chr15-78441765;