chr9-69035783-AT-A

Position:

• chr9-69035783-AT-A

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1_Strong PS1_Moderate PM2 PP5_Moderate

The NM_000144.5(FXN):​c.2delT​(p.Met1fs) variant causes a frameshift, start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000369 in 1,356,038 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000037 (0 hom.)
• Consequence: FXN NM_000144.5 frameshift, start_lost
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.25

Genes affected

FXN (HGNC:3951): (frataxin) This nuclear gene encodes a mitochondrial protein which belongs to the FRATAXIN family. The protein functions in regulating mitochondrial iron transport and respiration. The expansion of intronic trinucleotide repeat GAA from 8-33 repeats to >90 repeats results in Friedreich ataxia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2016]

ENSG00000285130 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 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 13 pathogenic variants in the truncated region.
• PS1: Another start lost variant in NM_000144.5 (FXN) was described as [Pathogenic] in Lovd
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 9-69035783-AT-A is Pathogenic according to our data. Variant chr9-69035783-AT-A is described in ClinVar as [Pathogenic]. Clinvar id is 3384335.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FXN	NM_000144.5	c.2delT	p.Met1fs	frameshift_variant, start_lost	1/5	ENST00000484259.3	NP_000135.2
FXN	NM_181425.3	c.2delT	p.Met1fs	frameshift_variant, start_lost	1/5		NP_852090.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FXN	ENST00000484259.3	c.2delT	p.Met1fs	frameshift_variant, start_lost	1/5	3	NM_000144.5	ENSP00000419243.2
ENSG00000285130	ENST00000642889.1	c.2delT	p.Met1fs	frameshift_variant, start_lost	1/25			ENSP00000493780.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000369 AC: 5 AN: 1356038 Hom.: 0 Cov.: 29 AF XY: 0.00000150 AC XY: 1 AN XY: 668624

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: 0.00

Gnomad4 NFE exome AF: 0.00000375

Gnomad4 OTH exome AF: 0.0000177

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 06, 2024

Initiation codon variant in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 12112211) -

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: rs149724959; hg19: chr9-71650699;