1-228165898-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001010867.4(IBA57):c.82A>G(p.Arg28Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000302 in 1,256,790 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. R28R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000030 (0 hom.)
• Consequence: IBA57 NM_001010867.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.15

Genes affected

IBA57 (HGNC:27302): (iron-sulfur cluster assembly factor IBA57) The protein encoded by this gene localizes to the mitochondrion and is part of the iron-sulfur cluster assembly pathway. The encoded protein functions late in the biosynthesis of mitochondrial 4Fe-4S proteins. Defects in this gene have been associated with autosomal recessive spastic paraplegia-74 and with multiple mitochondrial dysfunctions syndrome-3. Two transcript variants encoding different isoforms have been found for this gene. The smaller isoform is not likely to be localized to the mitochondrion since it lacks the amino-terminal transit peptide. [provided by RefSeq, Jul 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.16893956).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IBA57	NM_001010867.4	c.82A>G	p.Arg28Gly	missense_variant	1/3	ENST00000366711.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IBA57	ENST00000366711.4	c.82A>G	p.Arg28Gly	missense_variant	1/3	2	NM_001010867.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.0000302 AC: 38 AN: 1256790 Hom.: 0 Cov.: 30 AF XY: 0.0000340 AC XY: 21 AN XY: 616750

Gnomad4 AFR exome AF: 0.0000398

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: 0.00

Gnomad4 NFE exome AF: 0.0000334

Gnomad4 OTH exome AF: 0.0000581

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Multiple mitochondrial dysfunctions syndrome 3;C5568837:Hereditary spastic paraplegia 74 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Apr 11, 2022

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 28 of the IBA57 protein (p.Arg28Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with IBA57-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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. -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 21, 2023

The c.82A>G (p.R28G) alteration is located in exon 1 (coding exon 1) of the IBA57 gene. This alteration results from a A to G substitution at nucleotide position 82, causing the arginine (R) at amino acid position 28 to be replaced by a glycine (G). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.063
BayesDel_addAF	Benign	-0.10	T
BayesDel_noAF	Benign	-0.39
Cadd	Benign	16
Dann	Benign	0.81
DEOGEN2	Benign	0.0057	T
Eigen	Benign	-0.80
Eigen_PC	Benign	-0.78
FATHMM_MKL	Benign	0.075	N
LIST_S2	Benign	0.52	T
M_CAP	Pathogenic	0.37	D
MetaRNN	Benign	0.17	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.8	L
MutationTaster	Benign	1.0	N
PrimateAI	Pathogenic	0.83	D
PROVEAN	Benign	-1.5	N
REVEL	Benign	0.034
Sift	Benign	0.043	D
Sift4G	Uncertain	0.032	D
Polyphen		0.0020	B
Vest4		0.42
MutPred		0.32		Loss of methylation at R28 (P = 0.013);
MVP		0.24
MPC		0.33
ClinPred		0.16	T
GERP RS		2.6
Varity_R		0.093
gMVP		0.49

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: rs1263563131; hg19: chr1-228353599;