Many such ‘wild-type’ tumours have a deficiency in succinate dehydrogenase (SDH), which may be due to a variant in one of the SDH genes (A,B,C or D), which can be either sporadic or inherited, or due to epigenetic gene silencing, in which case the gene affected is usually SDHC. Specific advice concerning the management of patients with paediatric and adolescent, ‘wild-type’ and syndromic GIST can be obtained via the web site www.pawsgistclinic.org.uk. The gene discussed is SDHB; the disease is gastrointestinal stromal tumor.