22-50526650-A-C

Variant names:

• chr22-50526650-A-C
• rs121913042
• NM_001953.5:c.854T>G

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_001953.5(TYMP):​c.854T>G​(p.Leu285Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000142 in 1,411,794 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L285P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: TYMP NM_001953.5 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.48
• Publications: 0 publications found

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]

SCO2 Gene-Disease associations (from GenCC):

• cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• Leigh syndrome

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• myopia 6

  Inheritance: AD Classification: STRONG Submitted by: G2P
• autosomal recessive axonal charcot-marie-tooth disease due to copper metabolism defect

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_001953.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr22-50526650-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 16666.We mark this variant Likely_pathogenic, oryginal submission is: [Conflicting_classifications_of_pathogenicity].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.953
• PP5: Variant 22-50526650-A-C is Pathogenic according to our data. Variant chr22-50526650-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3684157.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TYMP	NM_001953.5	c.854T>G	p.Leu285Arg	missense_variant	Exon 7 of 10	ENST00000252029.8	NP_001944.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TYMP	ENST00000252029.8	c.854T>G	p.Leu285Arg	missense_variant	Exon 7 of 10	1	NM_001953.5	ENSP00000252029.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000142 AC: 2 AN: 1411794 Hom.: 0 Cov.: 36 AF XY: 0.00000286 AC XY: 2 AN XY: 698292

African (AFR) AF: 0.00 AC: 0 AN: 32346

American (AMR) AF: 0.00 AC: 0 AN: 38430

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25290

East Asian (EAS) AF: 0.00 AC: 0 AN: 36972

South Asian (SAS) AF: 0.00 AC: 0 AN: 80652

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 45162

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5702

European-Non Finnish (NFE) AF: 0.00000184 AC: 2 AN: 1088694

Other (OTH) AF: 0.00 AC: 0 AN: 58546

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Jun 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 285 of the TYMP protein (p.Leu285Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TYMP-related conditions. 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 TYMP protein function with a positive predictive value of 95%. This variant disrupts the p.Leu285 amino acid residue in TYMP. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16178026). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.33
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.47
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.94	D;.;D;D;D
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	.;D;.;D;T
M_CAP	Pathogenic	0.91	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.8	H;H;H;H;.
PhyloP100		3.5
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-4.7	D;D;D;D;D
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0020	D;D;D;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.81
MutPred		0.78		Gain of disorder (P = 0.0584);Gain of disorder (P = 0.0584);Gain of disorder (P = 0.0584);Gain of disorder (P = 0.0584);.;
MVP		0.94
MPC		1.6
ClinPred		0.99	D
GERP RS		3.8
PromoterAI		-0.027	Neutral
Varity_R		0.98
gMVP		0.90
Mutation Taster		=18/82	disease causing

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

Other links and lift over

dbSNP: rs121913042; hg19: chr22-50965079;