1-241519722-T-C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PVS1PS1_ModeratePM2PP5

The NM_000143.4(FH):c.1A>G(p.Met1?) variant causes a start lost change. The variant allele was found at a frequency of 0.00000324 in 1,543,456 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000022 ( 0 hom. )

Consequence

FH
NM_000143.4 start_lost

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:3

Conservation

PhyloP100: 4.13

Publications

7 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: Pathogenic. The variant received 13 ACMG points.

PVS1

Start lost variant, next in-frame start position is after 30 pathogenic variants. Next in-frame start position is after 44 codons. Genomic position: 241519593. Lost 0.085 part of the original CDS.

PS1

Another start lost variant in NM_000143.4 (FH) was described as [Likely_pathogenic] in ClinVar as 1067616

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-241519722-T-C is Pathogenic according to our data. Variant chr1-241519722-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 237113.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FH	NM_000143.4 link	c.1A>G	p.Met1?	start_lost	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.1A>G	p.Met1?	start_lost	Exon 1 of 10	1	NM_000143.4	ENSP00000355518.4		P07954-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152168

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000682

AC:

AN:

146594

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000936

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000216

AC:

AN:

1391288

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

685372

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

31098

American (AMR)

AF:

0.00

AC:

AN:

35394

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25024

East Asian (EAS)

AF:

0.0000564

AC:

AN:

35462

South Asian (SAS)

AF:

0.00

AC:

AN:

78570

European-Finnish (FIN)

AF:

0.00

AC:

AN:

48498

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4290

European-Non Finnish (NFE)

AF:

9.30e-7

AC:

AN:

1075426

Other (OTH)

AF:

0.00

AC:

AN:

57526

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

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:

0.0000131

AC:

AN:

152168

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74334

show subpopulations

African (AFR)

AF:

0.0000482

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68014

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1Uncertain:2

Aug 25, 2021

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Oct 03, 2023

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Initiation codon variant in a gene for which loss of function is a known mechanism of disease but an alternate initiation codon at Met44 could serve as an in-frame site (Dik et al., 2016); Published functional studies demonstrate that when this alternate start codon is used there is aberrant localization of the FH protein exclusively to the cytosol, without any mitochondrial targeting (Dik et al., 2016); This variant is associated with the following publications: (PMID: 27037871) -

Jun 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change affects the initiator methionine of the FH mRNA. The next in-frame methionine is located at codon 44. 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 0.009%). A different variant (c.1A>C) giving rise to the same protein effect has been determined to be pathogenic (PMID: 27037871). This suggests that this variant is also likely to be causative of disease. ClinVar contains an entry for this variant (Variation ID: 237113). 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. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely 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

Mar 05, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Oct 12, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.M1? variant (also known as c.1A>G), located in coding exon 1 of the FH gene, results from a A to G substitution at nucleotide position 1. This alters the methionine residue at the initiation codon. Variations that modify the initiation codon (ATG) are expected to result in either loss of translation initiation, N-terminal truncation, or cause a shift in the mRNA reading frame; however, there is an alternate in-frame methionine 44 amino acids from the initiation site. 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 nucleotide position is highly conserved in available vertebrate species. 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

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.51

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.25

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.28

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Uncertain

0.90

M_CAP

Pathogenic

0.97

MetaRNN

Pathogenic

0.89

MetaSVM

Pathogenic

1.1

PhyloP100

4.1

PROVEAN

Benign

-0.27

REVEL

Pathogenic

0.68

Sift

Uncertain

0.0090

Sift4G

Uncertain

0.014

Polyphen

0.32

Vest4

0.88

MutPred

0.62

Loss of loop (P = 0.1258);

MVP

0.94

ClinPred

0.83

GERP RS

5.3

PromoterAI

0.045

Neutral

(source)

Varity_R

0.43

gMVP

0.69

Mutation Taster

=38/162

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over