15-78149405-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_005530.3(IDH3A):c.2T>C(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00002 in 1,551,062 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000020 (0 hom.)
• Consequence: IDH3A NM_005530.3 start_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.53

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 Pathogenic. Variant got 10 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDH3A	NM_005530.3	c.2T>C	p.Met1?	start_lost	1/11	ENST00000299518.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDH3A	ENST00000299518.7	c.2T>C	p.Met1?	start_lost	1/11	1	NM_005530.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152174 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.000864

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000306 AC: 5 AN: 163412 Hom.: 0 AF XY: 0.0000330 AC XY: 3 AN XY: 90964

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.000497

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.000106

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000200 AC: 28 AN: 1398888 Hom.: 0 Cov.: 32 AF XY: 0.0000259 AC XY: 18 AN XY: 693722

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.000766

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000254

Gnomad4 NFE exome AF: 0.00000460

Gnomad4 OTH exome AF: 0.0000517

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152174 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74346

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.000864

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000546 Hom.: 0

Bravo AF: 0.0000151

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

Invitae

Jan 17, 2022

This sequence change affects the initiator methionine of the IDH3A mRNA. The next in-frame methionine is located at codon 51. 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 IDH3A-related conditions. ClinVar contains an entry for this variant (Variation ID: 1018005). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
Cadd	Benign	21
Dann	Uncertain	0.98
DEOGEN2	Benign	0.35	T;T;T;T;T
Eigen	Benign	-0.027
Eigen_PC	Benign	-0.010
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Uncertain	0.90	D;D;D;D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D
MetaSVM	Benign	-0.70	T
MutationTaster	Benign	1.0	D;D;D;D
PROVEAN	Benign	-0.68	N;N;N;N;.
REVEL	Uncertain	0.30
Sift	Pathogenic	0.0	D;D;D;D;.
Sift4G	Uncertain	0.033	D;D;D;D;D
Polyphen		0.10	B;.;.;.;.
Vest4		0.67
MutPred		1.0		Loss of MoRF binding (P = 0.1041);Loss of MoRF binding (P = 0.1041);Loss of MoRF binding (P = 0.1041);Loss of MoRF binding (P = 0.1041);Loss of MoRF binding (P = 0.1041);
MVP		0.81
ClinPred		0.96	D
GERP RS		3.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.83
gMVP		0.71

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: rs1353606657; hg19: chr15-78441747;