rs749266351

Positions:

• chr1-241500497-T-C
• chr1-241500497-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP3_Moderate PP5

The NM_000143.4(FH):​c.1330A>G​(p.Arg444Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 31)
• Consequence: FH NM_000143.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 2.32

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 Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.882
• PP5: Variant 1-241500497-T-C is Pathogenic according to our data. Variant chr1-241500497-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 573932.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FH	NM_000143.4	c.1330A>G	p.Arg444Gly	missense_variant	9/10	ENST00000366560.4	NP_000134.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FH	ENST00000366560.4	c.1330A>G	p.Arg444Gly	missense_variant	9/10	1	NM_000143.4	ENSP00000355518	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 24, 2022

For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt FH protein function. ClinVar contains an entry for this variant (Variation ID: 573932). This missense change has been observed in individual(s) with autosomal recessive fumarate hydratase deficiency (PMID: 33052056). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 444 of the FH protein (p.Arg444Gly). -

Fumarase deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Dec 08, 2022

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 03, 2024

The p.R444G variant (also known as c.1330A>G), located in coding exon 9 of the FH gene, results from an A to G substitution at nucleotide position 1330. The arginine at codon 444 is replaced by glycine, an amino acid with dissimilar properties. This alteration was identified as homozygous in a in a patient with fumarate hydratase deficiency (Peetsold M et al. J Child Neurol, 2020 Oct;:883073820962931). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this alteration is classified as likely pathogenic in association with autosomal recessive FH deficiency when present along with a second pathogenic or likely pathogenic variant on the other allele; however, the clinical significance for autosomal dominant HLRCC is unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.66
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.85	D
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.83	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.4	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-5.0	D
REVEL	Pathogenic	0.79
Sift	Uncertain	0.0080	D
Sift4G	Uncertain	0.022	D
Polyphen		0.54	P
Vest4		0.89
MutPred		0.58		Gain of methylation at K447 (P = 0.0487);
MVP		0.96
MPC		0.63
ClinPred		0.99	D
GERP RS		4.6
Varity_R		0.82
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs749266351; hg19: chr1-241663797;