12-108562641-TT-GG

Variant names:

• chr12-108562641-TT-GG
• rs67681514
• NM_213595.4:c.19_20delTTinsGG

Variant summary

Our verdict is Benign. The variant received -16 ACMG points: 0P and 16B. BP6_Very_Strong BA1

The NM_213595.4(ISCU):​c.19_20delTTinsGG​(p.Phe7Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. The variant is present in control chromosomes in GnomAd MNV project. The variant allele was found at a frequency of 0.859 in 110,974 alleles, including 48,105 homozygotes. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Benign (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. F7C) has been classified as Benign.

• Frequency: GnomAD MNV: 𝑓 0.86 Genomes: not found (cov: 35)
• Consequence: ISCU NM_213595.4 missense
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:4
• Conservation: PhyloP100: 2.46
• Publications: 5 publications found

Genes affected

ISCU (HGNC:29882): (iron-sulfur cluster assembly enzyme) This gene encodes a component of the iron-sulfur (Fe-S) cluster scaffold. Fe-S clusters are cofactors that play a role in the function of a diverse set of enzymes, including those that regulate metabolism, iron homeostasis, and oxidative stress response. Alternative splicing results in transcript variants encoding different protein isoforms that localize either to the cytosol or to the mitochondrion. Mutations in this gene have been found in patients with hereditary myopathy with lactic acidosis. A disease-associated mutation in an intron may activate a cryptic splice site, resulting in the production of a splice variant encoding a putatively non-functional protein. A pseudogene of this gene is present on chromosome 1. [provided by RefSeq, Feb 2016]

ISCU Gene-Disease associations (from GenCC):

• mitochondrial disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• hereditary myopathy with lactic acidosis due to ISCU deficiency

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet

ACMG classification

Our verdict: Benign. The variant received -16 ACMG points.

• BP6: Variant 12-108562641-TT-GG is Benign according to our data. Variant chr12-108562641-TT-GG is described in ClinVar as [Benign]. Clinvar id is 559220.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BA1: GnomAdMnv highest population allele frequency = 0.859 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ISCU	NM_213595.4	c.19_20delTTinsGG	p.Phe7Gly	missense_variant		ENST00000311893.14	NP_998760.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ISCU	ENST00000311893.14	c.19_20delTTinsGG	p.Phe7Gly	missense_variant		1	NM_213595.4	ENSP00000310623.9

Frequencies

GnomAD3 genomes Cov.: 35

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 35

GnomAD MNV AF: 0.859 AC: 110974 Hom.: 48105

ClinVar

Significance: Benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Benign:3

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 16, 2016

Mayo Clinic Laboratories, Mayo Clinic

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Aug 26, 2015

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary myopathy with lactic acidosis due to ISCU deficiency Benign:1

Dec 27, 2021

Fulgent Genetics, Fulgent Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.5

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs67681514; hg19: chr12-108956417; COSMIC: COSV108092780; COSMIC: COSV108092780;