rs786204827

chr22-41527315-G-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PS1 PM2 PP2 PP3_Strong

The NM_001098.3(ACO2):c.1981G>A(p.Gly661Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin Lovd. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G661A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: ACO2 NM_001098.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 9.33

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]

POLR3H (HGNC:30349): (RNA polymerase III subunit H) Enables DNA-directed 5'-3' RNA polymerase activity. Involved in transcription by RNA polymerase III. Located in centrosome and nucleoplasm. Part of RNA polymerase III complex. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PS1: Transcript NM_001098.3 (ACO2) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in Lovd
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, ACO2
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.978

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ACO2	NM_001098.3	c.1981G>A	p.Gly661Arg	missense_variant	16/18	ENST00000216254.9
POLR3H	NM_001018050.4	c.*1968C>T		3_prime_UTR_variant	6/6	ENST00000355209.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ACO2	ENST00000216254.9	c.1981G>A	p.Gly661Arg	missense_variant	16/18	1	NM_001098.3	P3
POLR3H	ENST00000355209.9	c.*1968C>T		3_prime_UTR_variant	6/6	1	NM_001018050.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 249968 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135236

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: 0.0000462

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461860 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000374

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

OPTIC ATROPHY 9, AUTOSOMAL RECESSIVE Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Dec 01, 2014

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 19, 2022

Experimental studies have shown that this missense change affects ACO2 function (PMID: 25351951). 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. ClinVar contains an entry for this variant (Variation ID: 189311). This missense change has been observed in individual(s) with clinical features of autosomal dominant ACO2-related conditions (PMID: 25351951, 34056600). This variant is present in population databases (rs752034900, gnomAD 0.004%). This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 661 of the ACO2 protein (p.Gly661Arg). 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	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.33	D
BayesDel_noAF	Pathogenic	0.24
Cadd	Pathogenic	34
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.89	D;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Uncertain	0.28	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.43	D
MutationAssessor	Pathogenic	4.5	H;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-7.7	D;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.012	D;D
Polyphen		1.0	D;D
Vest4		0.99
MutPred		0.89		.;Gain of MoRF binding (P = 0.0308);
MVP		0.90
MPC		1.4
ClinPred		1.0	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.92
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs752034900; hg19: chr22-41923319;