1-241500473-A-T

Position:

• chr1-241500473-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PP3_Moderate BS2

The NM_000143.4(FH):​c.1354T>A​(p.Ser452Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,776 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. S452S) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: FH NM_000143.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 4.91

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 0 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000143.4
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.911
• BS2: High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FH	NM_000143.4	c.1354T>A	p.Ser452Thr	missense_variant	9/10	ENST00000366560.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FH	ENST00000366560.4	c.1354T>A	p.Ser452Thr	missense_variant	9/10	1	NM_000143.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461776 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727188

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000696

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Nov 23, 2022	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 18, 2023	This sequence change replaces serine, which is neutral and polar, with threonine, which is neutral and polar, at codon 452 of the FH protein (p.Ser452Thr). 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: 566507). 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 with a positive predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Fumarase deficiency Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Apr 18, 2021

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 03, 2023

The p.S452T variant (also known as c.1354T>A), located in coding exon 9 of the FH gene, results from a T to A substitution at nucleotide position 1354. The serine at codon 452 is replaced by threonine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. 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
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.80	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Pathogenic	0.99	D
MutationAssessor	Pathogenic	3.6	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-2.8	D
REVEL	Pathogenic	0.84
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.77
MutPred		0.45		Gain of catalytic residue at M449 (P = 0.0334);
MVP		0.98
MPC		0.93
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.91
gMVP		0.98

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: rs201388169; hg19: chr1-241663773;