rs1157768121

chr1-241504156-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 8P and 4B. PM1 PM5 PP3_Strong BS2

The NM_000143.4(FH):c.994G>A(p.Ala332Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000867 in 1,614,032 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. A332P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: FH NM_000143.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 7.37

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 4 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 11 uncertain in NM_000143.4
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-241504156-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1709223.Status of the report is criteria_provided_single_submitter, 1 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983
• BS2: High AC in GnomAd at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FH	NM_000143.4	c.994G>A	p.Ala332Thr	missense_variant	7/10	ENST00000366560.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FH	ENST00000366560.4	c.994G>A	p.Ala332Thr	missense_variant	7/10	1	NM_000143.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152196 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

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: 0.0000588

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251282 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135800

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461836 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 727218

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000447

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000460 AC: 7 AN: 152196 Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4 AN XY: 74342

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000227

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	Invitae	Jan 15, 2024	This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 332 of the FH protein (p.Ala332Thr). This variant is present in population databases (no rsID available, gnomAD 0.006%). 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: 529820). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Nov 09, 2022	The variant has not been reported in the published literature. The frequency of this variant in the general population, 0.000014 (4/282678 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -

Fumarase deficiency Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Mar 12, 2020

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 25, 2023

The p.A332T variant (also known as c.994G>A), located in coding exon 7 of the FH gene, results from a G to A substitution at nucleotide position 994. The alanine at codon 332 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	Uncertain	0.51
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.58
Cadd	Pathogenic	28
Dann	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.3	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.72	T
PROVEAN	Uncertain	-3.8	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0060	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.84		Gain of glycosylation at A332 (P = 0.1726);
MVP		0.97
MPC		0.95
ClinPred		0.98	D
GERP RS		5.7
Varity_R		0.91
gMVP		0.96

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: rs1157768121; hg19: chr1-241667456;