While homozygous mutations of FH leads to fumaric aciduria (OMIM: 606812), a lethal metabolic disorder, its heterozygous mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC), a cancer syndrome characterized by uterine fibroids, cutaneous leiomyoma, and type 2 papillary renal cell cancer (Tomlinson et al., 2002). This evidence concerns the gene FH and hereditary leiomyomatosis and renal cell cancer.