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.

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.

People with this condition need donors

Joining a registry is a cheek swab and a short health form. 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