14-64449626-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_005956.4(MTHFD1):c.2457+4G>C variant causes a splice donor region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MTHFD1 NM_005956.4 splice_donor_region, intron
• Scores: Splicing: ADA: 0.0008089
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.431

Genes affected

ZBTB25 (HGNC:13112): (zinc finger and BTB domain containing 25) Predicted to enable DNA-binding transcription repressor activity, RNA polymerase II-specific and RNA polymerase II cis-regulatory region sequence-specific DNA binding activity. Predicted to be involved in regulation of transcription by RNA polymerase II. Located in nucleoplasm. [provided by Alliance of Genome Resources, Apr 2022]

MTHFD1 (HGNC:7432): (methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1) This gene encodes a protein that possesses three distinct enzymatic activities, 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase. Each of these activities catalyzes one of three sequential reactions in the interconversion of 1-carbon derivatives of tetrahydrofolate, which are substrates for methionine, thymidylate, and de novo purine syntheses. The trifunctional enzymatic activities are conferred by two major domains, an aminoterminal portion containing the dehydrogenase and cyclohydrolase activities and a larger synthetase domain. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.34924394).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MTHFD1	NM_005956.4	c.2457+4G>C		splice_donor_region_variant, intron_variant		ENST00000652337.1
ZBTB25	NM_001304508.1	c.186C>G	p.Thr62=	synonymous_variant	3/3
MTHFD1	NM_001364837.1	c.2457+4G>C		splice_donor_region_variant, intron_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MTHFD1	ENST00000652337.1	c.2457+4G>C		splice_donor_region_variant, intron_variant			NM_005956.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000313 Hom.: 0

Bravo AF: 0.00000378

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

Invitae

Mar 08, 2021

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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with MTHFD1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change falls in intron 24 of the MTHFD1 gene. It does not directly change the encoded amino acid sequence of the MTHFD1 protein. It affects a nucleotide within the consensus splice site of the intron. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.56
Cadd	Benign	5.9
Dann	Benign	0.97
Eigen	Uncertain	0.68
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.38	T
M_CAP	Benign	0.029	D
MetaRNN	Benign	0.35	T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	D;D;D;D;D
PROVEAN	Uncertain	-3.8	D
REVEL	Benign	0.20
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0080	D
Vest4		0.093
MutPred		0.39		Gain of MoRF binding (P = 0);
MVP		0.82
ClinPred		0.62	D
GERP RS		1.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00081
dbscSNV1_RF	Benign	0.12
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: rs2078338046; hg19: chr14-64916344;