rs1064796708

Variant names:

• chr1-241497916-A-C
• rs1064796708
• NM_000143.4:c.1445T>G

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000143.4(FH):​c.1445T>G​(p.Leu482*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. L482L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: FH NM_000143.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 6.62

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 16 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-241497916-A-C is Pathogenic according to our data. Variant chr1-241497916-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 423941.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FH	NM_000143.4	c.1445T>G	p.Leu482*	stop_gained	Exon 10 of 10	ENST00000366560.4	NP_000134.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FH	ENST00000366560.4	c.1445T>G	p.Leu482*	stop_gained	Exon 10 of 10	1	NM_000143.4	ENSP00000355518.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Aug 28, 2018

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The L482X nonsense variant in the FH gene has it been reported as a benign variant to our knowledge. This variant is predicted to cause loss of normal protein function through protein truncation. Based on currently available evidence, L482X is a strong candidate for a pathogenic variant. However, the possibility it is a rare benign variant cannot be excluded. -

Dec 08, 2023

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.Leu482*) in the FH gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 29 amino acid(s) of the FH protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with FH-related conditions. ClinVar contains an entry for this variant (Variation ID: 423941). This variant disrupts a region of the FH protein in which other variant(s) (p.Trp500*) have been determined to be pathogenic (PMID: 9635293, 21398687). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Fumarase deficiency Pathogenic:1

Jul 16, 2023

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Nov 04, 2022

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.L482* pathogenic mutation (also known as c.1445T>G), located in coding exon 10 of the FH gene, results from a T to G substitution at nucleotide position 1445. This changes the amino acid from a leucine to a stop codon within coding exon 10. This alteration occurs at the 3' terminus of theFH gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 29 amino acids of the protein. However, premature stop codons are typically deleterious in nature and the impacted region is critical for protein function (Ambry internal data). This alteration was identified in a patient with a personal history of papillary type 2 renal cell carcinoma (Al-Shinnag M et al. Front Oncol, 2021 Sep;11:738822). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.99	D
Vest4		0.89
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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: rs1064796708; hg19: chr1-241661216;