22-41499741-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM2 PP2 PP3 BP4

The NM_001098.3(ACO2):c.52C>T(p.Arg18Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000098 in 1,612,586 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. R18Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.00018 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000090 (0 hom.)
• Consequence: ACO2 NM_001098.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.53

Genes affected

ACO2 (HGNC:118): (aconitase 2) The protein encoded by this gene belongs to the aconitase/IPM isomerase family. It is an enzyme that catalyzes the interconversion of citrate to isocitrate via cis-aconitate in the second step of the TCA cycle. This protein is encoded in the nucleus and functions in the mitochondrion. It was found to be one of the mitochondrial matrix proteins that are preferentially degraded by the serine protease 15(PRSS15), also known as Lon protease, after oxidative modification. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, ACO2
• PP3: Multiple lines of computational evidence support a deleterious effect 5: Cadd, Dann, Eigen, MutationAssessor, PrimateAI [when max_spliceai, MetaRNN, MutationTaster was below the threshold]
• BP4: Computational evidence support a benign effect (MetaRNN=0.29740387).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACO2	NM_001098.3	c.52C>T	p.Arg18Trp	missense_variant	2/18	ENST00000216254.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACO2	ENST00000216254.9	c.52C>T	p.Arg18Trp	missense_variant	2/18	1	NM_001098.3	P3

Frequencies

GnomAD3 genomes AF: 0.000177 AC: 27 AN: 152186 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00207

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000735

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000184 AC: 46 AN: 250326 Hom.: 0 AF XY: 0.000155 AC XY: 21 AN XY: 135340

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00182

Gnomad NFE exome AF: 0.0000705

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000897 AC: 131 AN: 1460400 Hom.: 0 Cov.: 31 AF XY: 0.0000840 AC XY: 61 AN XY: 726542

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000176

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00194

Gnomad4 NFE exome AF: 0.0000162

Gnomad4 OTH exome AF: 0.0000663

GnomAD4 genome AF: 0.000177 AC: 27 AN: 152186 Hom.: 0 Cov.: 32 AF XY: 0.000242 AC XY: 18 AN XY: 74350

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00207

Gnomad4 NFE AF: 0.0000735

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000554 Hom.: 0

Bravo AF: 0.0000302

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.000157 AC: 19

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

Dec 09, 2023

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 18 of the ACO2 protein (p.Arg18Trp). This variant is present in population databases (rs201569120, gnomAD 0.2%). This variant has not been reported in the literature in individuals affected with ACO2-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt ACO2 protein function with a positive predictive value of 95%. 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
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Uncertain	0.085	D
BayesDel_noAF	Uncertain	0.080
Cadd	Pathogenic	33
Dann	Pathogenic	1.0
DEOGEN2	Uncertain	0.63	D;.
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.83	T;T
M_CAP	Uncertain	0.096	D
MetaRNN	Benign	0.30	T;T
MetaSVM	Benign	-0.31	T
MutationAssessor	Pathogenic	3.1	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-4.2	D;D
REVEL	Uncertain	0.39
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.81
MVP		0.79
MPC		1.5
ClinPred		0.84	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.65
gMVP		0.62

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs201569120; hg19: chr22-41895745;