For those purine and pyrimidine disorders that do present with symptoms, almost any system can be affected. Particular problems include kidney stones and renal disease (see entry Kidney disease), recurrent infections and severe immune deficiency, severe recurrent anaemia (anemia - US), muscle cramps and wasting, arthritis, neurological problems such as developmental delay, autism (see entry Autism Spectrum disorders, including Asperger syndrome) and seizures (see entry Epilepsy). They may also be responsible for adverse reactions to chemotherapy in patients undergoing treatment for cancer. Although originally thought to be childhood problems, it is clear that they may present at any age.
Symptoms may be severe and life-threatening.