Myopathy in hereditary leiomyomatosis and renal cell cancer in an extended family

Funding sources: none. Conflicts of interest: none declared. Dear Editor, Fumarate hydratase (FH) catalyses the conversion of fumarate to malate as part of the tricarboxylic acid (TCA) cycle.1 Germline mutations in the FH gene may lead to autosomal recessive mutations causing FH deficiency (FHD),2 associated with neurological impairment in childhood and muscular hypotonia.3 Patients with heterozygous mutations may develop multiple cutaneous leiomyomas (CLs) and uterine leiomyomas (ULs), and they more frequently have type II papillary renal cell cancer (RCC) [hereditary leiomyomatosis and RCC (HLRCC)].4 In most patients with HLRCC the mutations in FH are located before codon 250, whereas in FHD these mutations usually develop after codon 250.5 Skeletal muscle obtains most of its energy production from the TCA cycle. Therefore it may be postulated that patients with FH mutations might also develop skeletal muscle clinical dysfunction. We describe two patients and an extended family with pain and skeletal muscle cramps (PSMC).