1-241519682-AG-AGG

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PVS1PP5

The NM_000143.4(FH):c.40dupC(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:3U:3

Conservation

PhyloP100: 0.453

Publications

0 publications found

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 Gene-Disease associations (from GenCC):

hereditary leiomyomatosis and renal cell cancer
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Ambry Genetics, G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet
fumaric aciduria
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics
pheochromocytoma-paraganglioma
Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
leiomyosarcoma
Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
hereditary pheochromocytoma-paraganglioma
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

FH links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 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 482 pathogenic variants in the truncated region.

PP5

Variant 1-241519682-A-AG is Pathogenic according to our data. Variant chr1-241519682-A-AG is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 405920.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FH	NM_000143.4 link	c.40dupC	p.Leu14ProfsTer42	frameshift_variant	Exon 1 of 10	ENST00000366560.4	NP_000134.2	P07954-1A0A0S2Z4C3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FH	ENST00000366560.4 link	c.40dupC	p.Leu14ProfsTer42	frameshift_variant	Exon 1 of 10	1	NM_000143.4	ENSP00000355518.4		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

GnomAD2 exomes

AF:

0.0000275

AC:

AN:

145674

AF XY:

0.0000256

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 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

African (AFR)

AF:

0.0000318

AC:

AN:

31408

American (AMR)

AF:

0.0000281

AC:

AN:

35586

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25104

East Asian (EAS)

AF:

0.00

AC:

AN:

35660

South Asian (SAS)

AF:

0.00

AC:

AN:

78966

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48232

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4116

European-Non Finnish (NFE)

AF:

0.0000492

AC:

AN:

1077994

Other (OTH)

AF:

0.0000520

AC:

AN:

57728

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.491

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74348

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68020

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:2Uncertain:1

Apr 28, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Observed in a patient with an isolated cutaneous leiomyosarcoma and reduced FH enzyme activity and in individuals with paraganglioma or neuroendocrine tumor, but also seen in adult individuals tested at GeneDx without any personal or family history of HLRCC-related disease (PMID: 25913776, 34750850, 35988656); Frameshift 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 (PMID: 27037871); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 28300276, 33084842, 34750850, 25913776, 27037871, 35988656) -

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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;C1708350:Hereditary leiomyomatosis and renal cell cancer

Pathogenic:1

May 13, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Fumarase deficiency

Uncertain:1

Mar 20, 2024

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Jan 09, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.45

Mutation Taster

=5/195

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over