{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Fumarate hydratase (FH), or fumarase, is encoded by the FH gene, which is an enzymatic component of the tricarboxylic acid (TCA) cycle, or Krebs cycle, where it catalyzes the formation of L-malate from fumarate. Mutations in the FH gene can cause FH deficiency and lead to progressive encephalopathy. It was discovered that succinate dehydrogenase and FH are tumour suppressors and they are associated with metabolic dysfunction and tumorigenesis, providing biochemical evidence to explain enhanced glycolysis in tumours."}]},{"type":"paragraph","children":[{"type":"text","value":"Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC) is an autosomal dominant heritable syndrome with predisposition to development of Renal Cell Carcinoma and Smooth Muscle Tumors of the skin and uterus. Cells of individuals with HLRCC had lower FH enzyme activity than cells from normal controls, making FH enzyme activity testing a useful method for diagnosis and screening. Loss‐of‐function mutations of FH predisposes individuals to the autosomal dominant syndrome of Multiple Cutaneous and Uterine Leiomyomatosis (MCUL). Biallelic inactivation/mutations of FH are seen in 85% of Hereditary Leiomyomatosis and Renal Cell Carcinoma cases, 100% of Renal Cell Carcinoma with germline FH mutations, 19% of Papillary Renal Cell Carcinoma (Type II) have FH deficiency and 90% of FH deficiency RCC have FH mutations, 1% of unselected Leiomyomas, 2.6% of Leiomyomas in patients < 40 years old and 37- 52% of Leiomyoma with bizarre nuclei."}]}]}