NM_001953.5:c.1300+1G>T

Variant names:

• chr22-50526000-C-A
• rs1064792878
• NM_001953.5:c.1300+1G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001953.5(TYMP):​c.1300+1G>T variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000781 in 1,280,838 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 7.8e-7 (0 hom.)
• Consequence: TYMP NM_001953.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.21
• 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: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.09730849 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.5, offset of -22, new splice context is: gacGTgggt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TYMP	NM_001953.5	c.1300+1G>T		splice_donor_variant, intron_variant	Intron 9 of 9	ENST00000252029.8	NP_001944.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TYMP	ENST00000252029.8	c.1300+1G>T		splice_donor_variant, intron_variant	Intron 9 of 9	1	NM_001953.5	ENSP00000252029.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 7.81e-7 AC: 1 AN: 1280838 Hom.: 0 Cov.: 34 AF XY: 0.00000159 AC XY: 1 AN XY: 630272

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 25326

American (AMR) AF: 0.00 AC: 0 AN: 20598

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 21234

East Asian (EAS) AF: 0.00 AC: 0 AN: 28036

South Asian (SAS) AF: 0.0000151 AC: 1 AN: 66270

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 32192

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3778

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1030598

Other (OTH) AF: 0.00 AC: 0 AN: 52806

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Pathogenic	27
DANN	Uncertain	0.98
Eigen	Uncertain	0.46
Eigen_PC	Benign	0.12
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		3.2
GERP RS		2.8
PromoterAI		0.065	Neutral
Mutation Taster		=1/99	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.93		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.93		Position offset: 1

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

Other links and lift over

dbSNP: rs1064792878; hg19: chr22-50964429;