Early studies of two familial cancer syndromes, the multiple cutaneous and uterine leiomyomatosis (MCUL1), and the hereditary leiomyomatosis and renal cell cancer (HLRCC), implicated FH, a gene on chromosome 1q43 encoding the tricarboxylic acid cycle fumarate hydratase enzyme. Here, FH is linked to hereditary leiomyomatosis and renal cell cancer.