rs755587163

Positions:

• chr1-241508654-G-C
• chr1-241508654-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 6P and 4B. PM1 PM5 PP3_Moderate BS2

The NM_000143.4(FH):​c.687C>G​(p.Ile229Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000103 in 1,461,614 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I229T) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: FH NM_000143.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.01

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 2 ACMG points.

• PM1: In a strand (size 5) in uniprot entity FUMH_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000143.4
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-241508655-A-G is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.925
• BS2: High AC in GnomAdExome4 at 15 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FH	NM_000143.4	c.687C>G	p.Ile229Met	missense_variant	5/10	ENST00000366560.4	NP_000134.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FH	ENST00000366560.4	c.687C>G	p.Ile229Met	missense_variant	5/10	1	NM_000143.4	ENSP00000355518	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461614 Hom.: 0 Cov.: 31 AF XY: 0.0000151 AC XY: 11 AN XY: 727134

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000135

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 16, 2023

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. 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: 570079). This variant has not been reported in the literature in individuals affected with FH-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 229 of the FH protein (p.Ile229Met). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 24, 2024

The p.I229M variant (also known as c.687C>G), located in coding exon 5 of the FH gene, results from a C to G substitution at nucleotide position 687. The isoleucine at codon 229 is replaced by methionine, an amino acid with highly 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	Uncertain	0.40
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.30
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.92	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.75	T
PROVEAN	Uncertain	-2.8	D
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.61		Loss of methylation at K230 (P = 0.0473);
MVP		0.97
MPC		0.98
ClinPred		0.99	D
GERP RS		3.7
Varity_R		0.95
gMVP		0.87

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: rs755587163; hg19: chr1-241671954;