chr13-102618719-T-G

Variant names:

• chr13-102618719-T-G
• rs1555298364
• NM_001330588.2:c.496-3T>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001330588.2(TPP2):​c.496-3T>G variant causes a splice 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TPP2 NM_001330588.2 splice_region, intron
• Scores: Splicing: ADA: 0.9731
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.562
• Publications: 0 publications found

Genes affected

TPP2 (HGNC:12016): (tripeptidyl peptidase 2) This gene encodes a mammalian peptidase that, at neutral pH, removes tripeptides from the N terminus of longer peptides. The protein has a specialized function that is essential for some MHC class I antigen presentation. The protein is a high molecular mass serine exopeptidase; the amino acid sequence surrounding the serine residue at the active site is similar to the peptidases of the subtilisin class rather than the trypsin class. [provided by RefSeq, Jul 2008]

TPP2 Gene-Disease associations (from GenCC):

• immunodeficiency 78 with autoimmunity and developmental delay

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• autoimmune hemolytic anemia-autoimmune thrombocytopenia-primary immunodeficiency syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, max_spliceai. No scorers claiming Uncertain. Scorers claiming Benign: dbscSNV1_RF.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TPP2	NM_001330588.2	c.496-3T>G		splice_region_variant, intron_variant	Intron 4 of 29	ENST00000376052.5	NP_001317517.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TPP2	ENST00000376052.5	c.496-3T>G		splice_region_variant, intron_variant	Intron 4 of 29	5	NM_001330588.2	ENSP00000365220.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Evans syndrome, immunodeficiency, and premature immunosenescence associated with tripeptidyl-peptidase II deficiency Uncertain:1

Aug 31, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Variants that disrupt 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 may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 544306). This variant has not been reported in the literature in individuals affected with TPP2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 4 of the TPP2 gene. It does not directly change the encoded amino acid sequence of the TPP2 protein. It affects a nucleotide within the consensus splice site. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.70
CADD	Benign	18
DANN	Benign	0.56
PhyloP100		0.56

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Benign	0.62
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.44		Position offset: -41
DS_AL_spliceai		0.96		Position offset: 3

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

Other links and lift over

dbSNP: rs1555298364; hg19: chr13-103271069;