What are the symptoms? 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 conditions) 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. How is it treated? Specific treatment is only available for a small number of these conditions at present. Inheritance patterns and prenatal diagnosis Inheritance patternsThe mode of inheritance of these disorders is autosomal recessive, except Lesch Nyhan syndrome (HPRT deficiency) and phosphoribosylpyrophosphatesynthetase superactivity (PRPS) which are X-linked conditions, and familial juvenile hyperuricaemic nephropathy which is dominant. The degree of severity may be highly variable, even within the same family. Prenatal diagnosisPrenatal diagnosis is available for some of the purine and pyrimidine disorders. Is there support? Information and support in the UK for Purine and Pyrimidine Metabolic diseases is available from Metabolic Support UK (see entry Inherited Metabolic diseases).