NM_000270.4:c.11+2T>A

Variant names:

• chr14-20469537-T-A
• rs2139331878
• NM_000270.4:c.11+2T>A

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000270.4(PNP):​c.11+2T>A variant causes a splice donor, 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 pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PNP NM_000270.4 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.28
• Publications: 0 publications found

Genes affected

PNP (HGNC:7892): (purine nucleoside phosphorylase) This gene encodes an enzyme which reversibly catalyzes the phosphorolysis of purine nucleosides. The enzyme is trimeric, containing three identical subunits. Mutations which result in nucleoside phosphorylase deficiency result in defective T-cell (cell-mediated) immunity but can also affect B-cell immunity and antibody responses. Neurologic disorders may also be apparent in patients with immune defects. A known polymorphism at aa position 51 that does not affect enzyme activity has been described. A pseudogene has been identified on chromosome 2. [provided by RefSeq, Jul 2008]

PNP Gene-Disease associations (from GenCC):

• purine nucleoside phosphorylase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Orphanet

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.9, offset of 43, new splice context is: cagGTgctg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 14-20469537-T-A is Pathogenic according to our data. Variant chr14-20469537-T-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2862345.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000270.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PNP	NM_000270.4	MANE Select	c.11+2T>A		splice_donor intron	N/A	NP_000261.2	P00491

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PNP	ENST00000361505.10	TSL:1 MANE Select	c.11+2T>A		splice_donor intron	N/A	ENSP00000354532.6	P00491
	PNP	ENST00000556293.6	TSL:1	n.130+2T>A		splice_donor intron	N/A
	PNP	ENST00000557229.6	TSL:1	n.130+2T>A		splice_donor intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
1	-	-	Purine-nucleoside phosphorylase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.010
CADD	Pathogenic	34
DANN	Benign	0.93
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		3.3
GERP RS		4.8
PromoterAI		-0.60	Under-expression
RBP_binding_hub_radar		0.67
RBP_regulation_power_radar		1.8
Mutation Taster		=37/63	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.58		Position offset: 41
DS_DL_spliceai		1.0		Position offset: -2

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

Other links and lift over

dbSNP: rs2139331878; hg19: chr14-20937696;