chr9-69035816-C-G

Position:

• chr9-69035816-C-G

Variant summary

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

The NM_000144.5(FXN):​c.34C>G​(p.Leu12Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000735 in 1,360,340 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 (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.4e-7 (0 hom.)
• Consequence: FXN NM_000144.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.414

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]

(HGNC:):

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=0.12078196).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FXN	NM_000144.5	c.34C>G	p.Leu12Val	missense_variant	1/5	ENST00000484259.3	NP_000135.2
FXN	NM_181425.3	c.34C>G	p.Leu12Val	missense_variant	1/5		NP_852090.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FXN	ENST00000484259.3	c.34C>G	p.Leu12Val	missense_variant	1/5	3	NM_000144.5	ENSP00000419243	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 7.35e-7 AC: 1 AN: 1360340 Hom.: 0 Cov.: 29 AF XY: 0.00000149 AC XY: 1 AN XY: 670940

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: 0.0000130

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Sep 16, 2017

The p.Leu12Val variant has not been reported in the medical literature, is not listed in gene-specific variant databases, nor has it been previously identified in our laboratory. It is also absent from general population databases such as 1000 Genomes, the NHLBI GO Exome Sequencing Project (ESP), and the Genome Aggregation Database (gnomAD) browser. The leucine at codon 12 is weakly conserved considering 11 species (Alamut software v2.10.0), and computational analyses suggest that this variant does not affect the structure/function of the FXN protein (SIFT: tolerated, MutationTaster: polymorphism). However, based on the available information, the clinical significance of the p.Leu12Val variant cannot be determined with certainty. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.076
BayesDel_addAF	Uncertain	0.038	T
BayesDel_noAF	Benign	-0.18
CADD	Benign	14
DANN	Benign	0.86
DEOGEN2	Benign	0.34	T;.;.;T;.;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.15	N
LIST_S2	Benign	0.49	.;T;T;T;T;T
M_CAP	Uncertain	0.27	D
MetaRNN	Benign	0.12	T;T;T;T;T;T
MetaSVM	Uncertain	0.10	D
MutationAssessor	Benign	1.6	L;L;L;L;.;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-0.58	.;N;N;N;.;.
REVEL	Benign	0.24
Sift	Uncertain	0.013	.;D;D;T;.;.
Sift4G	Uncertain	0.022	.;D;D;.;.;.
Polyphen		0.29	B;P;.;B;.;.
Vest4		0.16, 0.24
MutPred		0.20		Gain of catalytic residue at L12 (P = 0.0419);Gain of catalytic residue at L12 (P = 0.0419);Gain of catalytic residue at L12 (P = 0.0419);Gain of catalytic residue at L12 (P = 0.0419);Gain of catalytic residue at L12 (P = 0.0419);Gain of catalytic residue at L12 (P = 0.0419);
MVP		0.57
ClinPred		0.27	T
GERP RS		-3.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.075
gMVP		0.23

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: rs1168839252; hg19: chr9-71650732;