Variant rs1060500900 details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1

The NM_000143.4(FH):c.40_41insC(p.Leu14ProfsTer42) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000394 in 1,546,966 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L14L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000042 ( 0 hom. )

Consequence

FH
NM_000143.4 frameshift

Scores

Not classified

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3

Conservation

PhyloP100: 0.453

Variant links:

Genes affected

FH (HGNC:3700): (fumarate hydratase) The protein encoded by this gene is an enzymatic component of the tricarboxylic acid (TCA) cycle, or Krebs cycle, and catalyzes the formation of L-malate from fumarate. It exists in both a cytosolic form and an N-terminal extended form, differing only in the translation start site used. The N-terminal extended form is targeted to the mitochondrion, where the removal of the extension generates the same form as in the cytoplasm. It is similar to some thermostable class II fumarases and functions as a homotetramer. Mutations in this gene can cause fumarase deficiency and lead to progressive encephalopathy. [provided by RefSeq, Jul 2008]

FH links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 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 379 pathogenic variants in the truncated region.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FH	NM_000143.4 linkuse as main transcript	c.40_41insC	p.Leu14ProfsTer42	frameshift_variant	1/10	ENST00000366560.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FH	ENST00000366560.4 linkuse as main transcript	c.40_41insC	p.Leu14ProfsTer42	frameshift_variant	1/10	1	NM_000143.4	P1	P07954-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000275

AC:

AN:

145674

Hom.:

AF XY:

0.0000256

AC XY:

AN XY:

78044

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000410

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000375

Gnomad OTH exome

AF:

0.000240

GnomAD4 exome

AF:

0.0000416

AC:

AN:

1394794

Hom.:

Cov.:

AF XY:

0.0000422

AC XY:

AN XY:

687692

show subpopulations

Gnomad4 AFR exome

AF:

0.0000318

Gnomad4 AMR exome

AF:

0.0000281

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:

0.0000492

Gnomad4 OTH exome

AF:

0.0000520

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74348

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000264

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Sep 08, 2023	Nonsense variant in a gene for which loss-of-function is a known mechanism of disease; however, a downstream in-frame ATG could serve as an alternate initiator codon (Dik et al., 2016); Observed in an individual with a head and neck paraganglioma, and another with an isolated cutaneous leiomyosarcoma and reduced FH enzyme activity (Weiler et al., 2016; Parisien-La Salle et al., 2022); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 28300276, 33084842, 27037871, 25913776, 34750850) -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 26, 2024	This sequence change creates a premature translational stop signal (p.Leu14Profs*42) in the FH gene. FH has two initiator codons, p.Met1 and p.Met44, which result in two different functional isoforms that localize to the mitochondria and cytosol, respectively (PMID: 21929734, 27037871). Loss-of-function variants in FH are known to be pathogenic (PMID: 11865300, 21398687). Variants affecting the mitochondrial isoform confer risk for fumarate hydratase deficiency, while variants that affect the cytosolic isoform confer risk for FH tumor predisposition syndrome. This variant is present in population databases (no rsID available, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with a primary cutaneous leiomyosarcoma (PMID: 25913776). ClinVar contains an entry for this variant (Variation ID: 405920). This variant disrupts the mitochondria-targeting sequence (MTS) of the FH protein, which is important for protein import into the mitochondria (PMID: 27037871). This suggests that disruption of this region is causative of fumarate hydratase deficiency. For these reasons, this variant has been classified as Pathogenic for autosomal recessive fumarate hydratase deficiency. However, this variant is not likely to confer risk for autosomal dominant FH tumor predisposition syndrome. -

Fumarase deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Oct 18, 2023

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 20, 2023

The c.40dupC variant, located in coding exon 1 of the FH gene, results from a duplication of C at nucleotide position 40, causing a translational frameshift with a predicted alternate stop codon (p.L14Pfs*42). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, there is a second in-frame methionine at p.M44. Proteins initiated from the first methionine are targeted to the mitochondrion while proteins initiated from the second methionine are targeted to the cytoplasm due to the lack of the mitochondrial targeting sequence encoded between them (Dik E et al. Traffic, 2016 Jul;17:720-32, Magrane M et al., Database (Oxford) 2011; bar009). Data suggest that it is the cytoplasmic protein that conveys the tumor suppressor function of FH (Yogev O et al. PLoS Biol., 2010 Mar;8:e1000328). This alteration was detected in an individual with a single cutaneous leiomyoma and two small uterine fibroids at age 72, whose father had kidney cancer diagnosed at age 58. Of note, this patient had 45% fumarase activity in her blood (Weiler L et al. Br. J. Dermatol., 2015 Apr;175:1104-06). This variant, designated as c.40dup (p.Leu14fs) has been reported in a French cohort of individuals with HLRCC (Muller M et al. Clin Genet, 2017 Dec;92:606-615). This alteration and others that are expected to adversely affect the protein before the second methionine, have been observed in numerous individuals who do not have a personal or family history that is consistent with or suggestive of HLRCC (Ambry internal data). The clinical impact of this variant in terms of the fumarase deficiency is also unclear due to the lack of this variant being associated with this autosomal recessive disease in the literature and internally. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over