2-208237162-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_005896.4(IDH1):c.1162C>T(p.Arg388Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 1,445,658 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R388S) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: IDH1 NM_005896.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.60

Genes affected

IDH1 (HGNC:5382): (isocitrate dehydrogenase (NADP(+)) 1) 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. Each NADP(+)-dependent isozyme is a homodimer. The protein encoded by this gene is the NADP(+)-dependent isocitrate dehydrogenase found in the cytoplasm and peroxisomes. It contains the PTS-1 peroxisomal targeting signal sequence. The presence of this enzyme in peroxisomes suggests roles in the regeneration of NADPH for intraperoxisomal reductions, such as the conversion of 2, 4-dienoyl-CoAs to 3-enoyl-CoAs, as well as in peroxisomal reactions that consume 2-oxoglutarate, namely the alpha-hydroxylation of phytanic acid. The cytoplasmic enzyme serves a significant role in cytoplasmic NADPH production. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Sep 2013]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.41352707).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDH1	NM_005896.4	c.1162C>T	p.Arg388Cys	missense_variant	10/10	ENST00000345146.7
IDH1	NM_001282386.1	c.1162C>T	p.Arg388Cys	missense_variant	10/10
IDH1	NM_001282387.1	c.1162C>T	p.Arg388Cys	missense_variant	10/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDH1	ENST00000345146.7	c.1162C>T	p.Arg388Cys	missense_variant	10/10	1	NM_005896.4	P1
IDH1	ENST00000415913.5	c.1162C>T	p.Arg388Cys	missense_variant	10/10	1		P1
IDH1	ENST00000446179.5	c.1162C>T	p.Arg388Cys	missense_variant	10/10	1		P1
IDH1	ENST00000484575.1	n.624C>T		non_coding_transcript_exon_variant	3/3	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000405 AC: 1 AN: 246888 Hom.: 0 AF XY: 0.00000749 AC XY: 1 AN XY: 133452

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000291

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000131 AC: 19 AN: 1445658 Hom.: 0 Cov.: 26 AF XY: 0.0000139 AC XY: 10 AN XY: 720156

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000672

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: 0.0000146

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 12, 2022

The p.R388C variant (also known as c.1162C>T), located in coding exon 8 of the IDH1 gene, results from a C to T substitution at nucleotide position 1162. The arginine at codon 388 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is conserved. In addition, the in silico prediction for this alteration is inconclusive. 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	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.80	D;D;D
Eigen	Uncertain	0.36
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Uncertain	0.94	D
M_CAP	Uncertain	0.14	D
MetaRNN	Benign	0.41	T;T;T
MetaSVM	Uncertain	0.058	D
MutationAssessor	Pathogenic	4.0	H;H;H
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-2.3	N;N;N
REVEL	Uncertain	0.56
Sift	Uncertain	0.0040	D;D;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		0.045	B;B;B
Vest4		0.51
MVP		0.89
MPC		0.72
ClinPred		0.71	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.85
gMVP		0.89

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs1168592559; hg19: chr2-209101886;