1-228165884-TGC-T

Variant names:

• chr1-228165884-TGC-T
• rs1454220856
• NM_001010867.4:c.74_75delCG

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001010867.4(IBA57):​c.74_75delCG​(p.Ala25GlyfsTer52) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000336 in 1,190,032 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: IBA57 NM_001010867.4 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.431

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 Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 28 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-228165884-TGC-T is Pathogenic according to our data. Variant chr1-228165884-TGC-T is described in ClinVar as [Pathogenic]. Clinvar id is 1997279.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IBA57	NM_001010867.4	c.74_75delCG	p.Ala25GlyfsTer52	frameshift_variant	Exon 1 of 3	ENST00000366711.4	NP_001010867.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IBA57	ENST00000366711.4	c.74_75delCG	p.Ala25GlyfsTer52	frameshift_variant	Exon 1 of 3	2	NM_001010867.4	ENSP00000355672.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000336 AC: 4 AN: 1190032 Hom.: 0 AF XY: 0.00000173 AC XY: 1 AN XY: 578294

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: 0.0000355

Gnomad4 NFE exome AF: 0.00000305

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

May 21, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals affected with IBA57-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Ala25Glyfs*52) in the IBA57 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in IBA57 are known to be pathogenic (PMID: 23462291, 25971455, 27785568, 28671726). -

Computational scores

Source: dbNSFP v4.3

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: rs1454220856; hg19: chr1-228353585;