1-241512143-C-T

Position:

• chr1-241512143-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000143.4(FH):​c.379G>A​(p.Val127Ile) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. 2/3 splice prediction tools predicting alterations to normal splicing. 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. V127L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FH NM_000143.4 missense, splice_region
• Scores: Splicing: ADA: 0.9969
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.51

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]

FH (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 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, 12 uncertain in NM_000143.4
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FH	NM_000143.4	c.379G>A	p.Val127Ile	missense_variant, splice_region_variant	4/10	ENST00000366560.4	NP_000134.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FH	ENST00000366560.4	c.379G>A	p.Val127Ile	missense_variant, splice_region_variant	4/10	1	NM_000143.4	ENSP00000355518.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 11, 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant  is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 2070913). 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 valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 127 of the FH protein (p.Val127Ile). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D
Eigen	Benign	0.058
Eigen_PC	Benign	0.22
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.57	D
MetaRNN	Uncertain	0.58	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Benign	1.3	L
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-0.79	N
REVEL	Uncertain	0.60
Sift	Uncertain	0.024	D
Sift4G	Benign	0.30	T
Polyphen		0.088	B
Vest4		0.44
MutPred		0.60		Gain of catalytic residue at L132 (P = 0.0545);
MVP		0.91
MPC		0.29
ClinPred		0.94	D
GERP RS		4.9
Varity_R		0.58
gMVP		0.69

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.75
SpliceAI score (max)		0.28		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.28		Position offset: -48

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr1-241675443;