22-50525780-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001953.5(TYMP):c.1439C>G(p.Pro480Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000048 in 1,458,468 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign 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. P480A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: TYMP NM_001953.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: -0.391

Genes affected

TYMP (HGNC:3148): (thymidine phosphorylase) This gene encodes an angiogenic factor which promotes angiogenesis in vivo and stimulates the in vitro growth of a variety of endothelial cells. It has a highly restricted target cell specificity acting only on endothelial cells. Mutations in this gene have been associated with mitochondrial neurogastrointestinal encephalomyopathy. Multiple alternatively spliced transcript variants have been identified. [provided by RefSeq, Apr 2012]

SCO2 (HGNC:10604): (synthesis of cytochrome C oxidase 2) Cytochrome c oxidase (COX) catalyzes the transfer of electrons from cytochrome c to molecular oxygen, which helps to maintain the proton gradient across the inner mitochondrial membrane that is necessary for aerobic ATP production. Human COX is a multimeric protein complex that requires several assembly factors; this gene encodes one of the COX assembly factors. The encoded protein is a metallochaperone that is involved in the biogenesis of cytochrome c oxidase subunit II. Mutations in this gene are associated with fatal infantile encephalocardiomyopathy and myopia 6. [provided by RefSeq, Oct 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.11062449).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TYMP	NM_001953.5	c.1439C>G	p.Pro480Arg	missense_variant	10/10	ENST00000252029.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TYMP	ENST00000252029.8	c.1439C>G	p.Pro480Arg	missense_variant	10/10	1	NM_001953.5	P2

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome AF: 0.00000480 AC: 7 AN: 1458468 Hom.: 0 Cov.: 38 AF XY: 0.00000689 AC XY: 5 AN XY: 725536

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: 0.00000630

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 35

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Mitochondrial neurogastrointestinal encephalomyopathy Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Sep 16, 2020

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 12, 2014

The P480R variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. Mutations in the TYMP gene are associated with the autosomal recessive disorder mitochondrial DNA depletion syndrome 1 (MNGIE Type). The P480R variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species. In silico analysis predicts this variant likely does not alter the protein structure/function. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. The variant is found in MITONUC-MITOP panel(s). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.075
BayesDel_addAF	Uncertain	0.045	T
BayesDel_noAF	Benign	-0.17
Cadd	Benign	18
Dann	Benign	0.95
DEOGEN2	Benign	0.13	T;.;T;T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Uncertain	0.85	D
M_CAP	Pathogenic	0.42	D
MetaRNN	Benign	0.11	T;T;T;T
MetaSVM	Uncertain	0.036	D
MutationAssessor	Benign	1.1	L;.;L;L
MutationTaster	Benign	1.0	N;N;N;N;N;N
PrimateAI	Uncertain	0.65	T
PROVEAN	Benign	-0.030	N;N;N;N
REVEL	Benign	0.28
Sift	Benign	0.041	D;D;D;D
Sift4G	Uncertain	0.037	D;D;D;D
Polyphen		0.0	B;.;B;B
Vest4		0.17
MutPred		0.27		Gain of solvent accessibility (P = 3e-04);.;Gain of solvent accessibility (P = 3e-04);Gain of solvent accessibility (P = 3e-04);
MVP		0.73
MPC		0.77
ClinPred		0.13	T
GERP RS		-1.8
Varity_R		0.10
gMVP		0.28

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: rs863224256; hg19: chr22-50964209;