2-208237104-A-T

Position:

• chr2-208237104-A-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_005896.4(IDH1):​c.1220T>A​(p.Ile407Asn) 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. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: IDH1 NM_005896.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.559

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.04664755).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDH1	NM_005896.4	c.1220T>A	p.Ile407Asn	missense_variant	10/10	ENST00000345146.7
IDH1	NM_001282386.1	c.1220T>A	p.Ile407Asn	missense_variant	10/10
IDH1	NM_001282387.1	c.1220T>A	p.Ile407Asn	missense_variant	10/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDH1	ENST00000345146.7	c.1220T>A	p.Ile407Asn	missense_variant	10/10	1	NM_005896.4	P1
IDH1	ENST00000415913.5	c.1220T>A	p.Ile407Asn	missense_variant	10/10	1		P1
IDH1	ENST00000446179.5	c.1220T>A	p.Ile407Asn	missense_variant	10/10	1		P1
IDH1	ENST00000484575.1	n.682T>A		non_coding_transcript_exon_variant	3/3	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 33

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

Jun 29, 2021

The p.I407N variant (also known as c.1220T>A), located in coding exon 8 of the IDH1 gene, results from a T to A substitution at nucleotide position 1220. The isoleucine at codon 407 is replaced by asparagine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. 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	Benign	0.061
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.41
CADD	Benign	16
DANN	Benign	0.95
DEOGEN2	Benign	0.059	T;T;T
Eigen	Benign	-0.77
Eigen_PC	Benign	-0.67
FATHMM_MKL	Benign	0.15	N
M_CAP	Benign	0.019	T
MetaRNN	Benign	0.047	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.0	N;N;N
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	0.58	N;N;N
REVEL	Benign	0.12
Sift	Benign	0.30	T;T;T
Sift4G	Benign	0.24	T;T;T
Polyphen		0.0	B;B;B
Vest4		0.25
MutPred		0.38		Gain of disorder (P = 0.0041);Gain of disorder (P = 0.0041);Gain of disorder (P = 0.0041);
MVP		0.61
MPC		0.31
ClinPred		0.072	T
GERP RS		-1.2
Varity_R		0.14
gMVP		0.66

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: chr2-209101828;