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Disease Profile

Purine nucleoside phosphorylase deficiency

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

PNP deficiency


Congenital and Genetic Diseases; Immune System Diseases; Metabolic disorders


Purine nucleoside phosphorylase (PNP) deficiency is a disorder of the immune system (primary immunodeficiency) characterized by recurrent infections, neurologic symptoms, and autoimmune disorders. PNP deficiency causes a shortage of white blood cells, called T-cells, that help fight infection. Some people with this condition develop neurologic symptoms, such as stiff or rigid muscles (spasticity), uncoordinated movements (ataxia), developmental delay, and intellectual disability.[1][2][3] In addition, PNP deficiency is associated with an increased risk to develop autoimmune disorders, such as autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura (ITP), autoimmune neutropenia, thyroiditis, and lupus.[1][3] ?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /PNP deficiency is caused by mutations in the PNP gene and is inherited in an autosomal recessive manner. Treatment with bone marrow transplantation can improve the immune system problems associated with this condition, but does not improve the neurologic symptoms.[1][2][3]


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Decreased urinary urate
30%-79% of people have these symptoms
Autoimmune hemolytic anemia
Humoral immunodeficiency
Low blood uric acid levels
Recurrent respiratory infections
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections

[ more ]

Severe combined immunodeficiency
Unusual gastrointestinal infection
5%-29% of people have these symptoms
Cerebral palsy
Decreased proportion of CD3-positive T cells
Global developmental delay
More active than typical
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Decreased blood lymphocyte number
Low lymphocyte number

[ more ]

Muscular hypotonia
Low or weak muscle tone
Spastic paraparesis
1%-4% of people have these symptoms
Autoimmune thrombocytopenia
Sensorineural hearing impairment
Systemic lupus erythematosus


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
  • Orphanet lists international laboratories offering diagnostic testing for this condition.

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Purine nucleoside phosphorylase deficiency. Click on the link to view a sample search on this topic.


  1. Knutsen AP. Purine Nucleoside Phosphorylase Deficiency. Medscape. Sep 22, 2015; https://emedicine.medscape.com/article/887823. Accessed 10/5/2016.
  2. purine nucleoside phosphorylase deficiency. Genetics Home Reference. April 2012; https://ghr.nlm.nih.gov/condition/purine-nucleoside-phosphorylase-deficiency. Accessed 10/5/2016.
  3. Pr Eyal Grunebaum. Purine nucleoside phosphorylase deficiency. Orphanet. April 2015; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=760. Accessed 10/5/2016.
  4. CF Classen, AS Schulz, M Sigl-Kraetzig, GF Hoffmann, HA Simmonds, L Fairbanks, KM Debatin, W Friedrich. Successful HLA-identical bone marrow transplantation in a patient with PNP deficiency using busulfan and fludarabine for conditioning. Bone Marrow Transplantation. July 1, 2001; 28:93-96. https://www.nature.com/bmt/journal/v28/n1/full/1703100a.html. Accessed 10/5/2016.