NM_000144.5:c.340_352delGCAGACAAGCCAT

Variant names:

• chr9-69053214-TTGCAGACAAGCCA-T
• rs147211454
• NM_000144.5:c.340_352delGCAGACAAGCCAT

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1

The NM_000144.5(FXN):​c.340_352delGCAGACAAGCCAT​(p.Ala114ThrfsTer15) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000137 in 1,461,740 control chromosomes in the GnomAD database, with no homozygous occurrence. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FXN NM_000144.5 frameshift
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.11
• Publications: 0 publications found

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]

FXN Gene-Disease associations (from GenCC):

• Friedreich ataxia

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Friedreich ataxia 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• Friedreich ataxia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000285130 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000144.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FXN	NM_000144.5	MANE Select	c.340_352delGCAGACAAGCCAT	p.Ala114ThrfsTer15	frameshift	Exon 3 of 5	NP_000135.2
	FXN	NM_181425.3		c.340_352delGCAGACAAGCCAT	p.Ala114ThrfsTer15	frameshift	Exon 3 of 5	NP_852090.1	Q16595-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FXN	ENST00000484259.3	TSL:3 MANE Select	c.340_352delGCAGACAAGCCAT	p.Ala114ThrfsTer15	frameshift	Exon 3 of 5	ENSP00000419243.2	Q16595-1
	FXN	ENST00000377270.8	TSL:1	c.115_127delGCAGACAAGCCAT	p.Ala39ThrfsTer15	frameshift	Exon 4 of 6	ENSP00000366482.4	C9JAX1
	FXN	ENST00000498653.5	TSL:1	c.115_127delGCAGACAAGCCAT	p.Ala39ThrfsTer15	frameshift	Exon 3 of 5	ENSP00000418015.1	C9JAX1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251486 AF XY: 0.00000736

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461740 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 727176

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53402

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111932

Other (OTH) AF: 0.00 AC: 0 AN: 60380

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00666416), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.1
Mutation Taster		=0/200	disease causing (fs/PTC)

Splicing

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

Other links and lift over

dbSNP: rs147211454; hg19: chr9-71668130;