Jada Bascom Foundation
All conditions

Inherited immune disorders

Purine nucleoside phosphorylase deficiency

Also called: PNP deficiency · PNP-SCID · PNP-def · PNP-associated combined immunodeficiency · Purine-nucleoside phosphorylase deficiency

What a donor has to do with this

For some people with this condition, a transplant using blood stem cells from an unrelated donor is part of the treatment guidelines. When a transplant is the right route and no one in the family matches, that donor comes from a registry. Not everyone with this condition has a transplant, and many never need one.

This is our reading of published transplant guidelines for this condition, not a measurement of how many people need a donor. Where a source actually counted donors, the figure and the people it counted are shown further down. Where none did, we say so rather than estimate.

This page is not written out in full yet

We have not written this condition out in full yet. What is on this page — how a donor fits in, who it affects, and the sources behind that — is researched and linked, but the plain-English explanation of the condition itself is still to come.

What the evidence says

Who it affects
Typical onset/diagnosis: both sexes usually present in infancy or early childhood; in a 46-patient international cohort, median presentation was 7.5 months (range 1–48). Evidence: EBMT study across 21 centers (published 2026); no markedly enriched population was identified.
Treatments other than a transplant
Immunoglobulin replacement and antimicrobial prophylaxis — supportive/bridge to HCT — multiple regions — Controls infection risk but does not correct purine toxicity or established neurologic injury.
If a transplant is used, the cells come from
bone marrow: used in the opened disease-specific transplant report; mobilized peripheral blood stem cells: used in an opened unrelated-donor case; umbilical cord blood: used in the opened disease-specific transplant literature; dominance: no dominant graft source was reported in the opened disease-specific sources
How often the donor was unrelated
Not reported. No source we could read states this for this condition, so we do not give a number. An estimate here would be a guess dressed as evidence.

Where this gets complicated

The 2026 EBMT international 21-center cohort of 46 patients reported 3-year overall/event-free survival of 86%/75%; neurologic abnormalities were present in 88% at HCT.; HCT corrects immune deficiency, but pre-existing neurologic injury may persist; no unrelated-donor percentage was inferred.

Registries need people

Joining a registry is a cheek swab and a short health form. You are not matched to a condition — you are matched to a person, and it could be someone with any of the conditions in this library. You are contacted only if you turn out to be a possible match for someone, and you can ask questions and decline before anything else happens.

Find your registry

Related conditions

Others in inherited immune disorders. They are genuinely different diseases with different treatments — the group name is not a diagnosis.

Where this came from

Purine nucleoside phosphorylase deficiency — what a bone marrow donor has to do with it | Jada Bascom Foundation